Update terraform plugin SDK from 1.0.0 to 1.7.0

[pdecat]

This PR updates the terraform-plugin-sdk from 1.0.0 to 1.7.0:

go get -u github.com/hashicorp/terraform-plugin-sdk
go mod tidy
rm -rf vendor/
go mod vendor
git add .

This resolves an issue I faced while working on another PR:

# make testacc TEST=./pagerduty TESTARGS='-run=TestAccPagerDutyExtension -count=1'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./pagerduty -v -run=TestAccPagerDutyExtension -count=1 -timeout 120m
# github.com/hashicorp/terraform-plugin-sdk/internal/earlyconfig
../../../../pkg/mod/github.com/hashicorp/terraform-plugin-sdk@v1.0.0/internal/earlyconfig/config.go:89:20: cannot range over reqs (type *tfconfig.ProviderRequirement)
FAIL    github.com/terraform-providers/terraform-provider-pagerduty/pagerduty [build failed]
FAIL
make: *** [GNUmakefile:17: testacc] Error 2

See https://github.com/terraform-providers/terraform-provider-datadog/pull/346#issuecomment-581876259 for a similar issue and resolution.

[pdecat]

Acceptance test results:

# make testacc TEST=./pagerduty TESTARGS='-count=1'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./pagerduty -v -count=1 -timeout 120m
=== RUN   TestConfigEmptyToken
--- PASS: TestConfigEmptyToken (0.00s)
=== RUN   TestConfigSkipCredsValidation
2020/03/09 16:11:29 [INFO] PagerDuty client configured
--- PASS: TestConfigSkipCredsValidation (0.00s)
=== RUN   TestAccDataSourcePagerDutyEscalationPolicy_Basic
--- PASS: TestAccDataSourcePagerDutyEscalationPolicy_Basic (10.55s)
=== RUN   TestAccDataSourcePagerDutyExtensionSchema_Basic
--- PASS: TestAccDataSourcePagerDutyExtensionSchema_Basic (4.81s)
=== RUN   TestAccDataSourcePagerDutySchedule_Basic
--- PASS: TestAccDataSourcePagerDutySchedule_Basic (10.29s)
=== RUN   TestAccDataSourcePagerDutyService_Basic
--- PASS: TestAccDataSourcePagerDutyService_Basic (11.43s)
=== RUN   TestAccDataSourcePagerDutyTeam_Basic
--- PASS: TestAccDataSourcePagerDutyTeam_Basic (6.20s)
=== RUN   TestAccDataSourcePagerDutyUser_Basic
--- PASS: TestAccDataSourcePagerDutyUser_Basic (8.10s)
=== RUN   TestAccDataSourcePagerDutyVendor_Basic
--- PASS: TestAccDataSourcePagerDutyVendor_Basic (4.60s)
=== RUN   TestAccDataSourcePagerDutyVendor_ExactMatch
--- PASS: TestAccDataSourcePagerDutyVendor_ExactMatch (4.70s)
=== RUN   TestAccDataSourcePagerDutyVendor_SpecialChars
--- PASS: TestAccDataSourcePagerDutyVendor_SpecialChars (4.63s)
=== RUN   TestAccPagerDutyEscalationPolicy_import
--- PASS: TestAccPagerDutyEscalationPolicy_import (8.76s)
=== RUN   TestAccPagerDutyEventRule_import
--- PASS: TestAccPagerDutyEventRule_import (5.11s)
=== RUN   TestAccPagerDutyExtension_import
--- PASS: TestAccPagerDutyExtension_import (12.32s)
=== RUN   TestAccPagerDutyMaintenanceWindow_import
--- PASS: TestAccPagerDutyMaintenanceWindow_import (11.13s)
=== RUN   TestAccPagerDutySchedule_import
--- PASS: TestAccPagerDutySchedule_import (9.52s)
=== RUN   TestAccPagerDutyServiceIntegration_import
--- PASS: TestAccPagerDutyServiceIntegration_import (12.94s)
=== RUN   TestAccPagerDutyService_import
--- PASS: TestAccPagerDutyService_import (9.90s)
=== RUN   TestAccPagerDutyServiceWithIncidentUrgency_import
--- PASS: TestAccPagerDutyServiceWithIncidentUrgency_import (10.18s)
=== RUN   TestAccPagerDutyTeamMembership_import
--- PASS: TestAccPagerDutyTeamMembership_import (8.59s)
=== RUN   TestAccPagerDutyTeam_import
--- PASS: TestAccPagerDutyTeam_import (6.12s)
=== RUN   TestAccPagerDutyUserContactMethod_import
--- PASS: TestAccPagerDutyUserContactMethod_import (8.48s)
=== RUN   TestAccPagerDutyUser_import
--- PASS: TestAccPagerDutyUser_import (7.81s)
=== RUN   TestProvider
--- PASS: TestProvider (0.00s)
=== RUN   TestProviderImpl
--- PASS: TestProviderImpl (0.00s)
=== RUN   TestAccPagerDutyAddon_Basic
--- PASS: TestAccPagerDutyAddon_Basic (8.08s)
=== RUN   TestAccPagerDutyEscalationPolicy_Basic
--- PASS: TestAccPagerDutyEscalationPolicy_Basic (13.35s)
=== RUN   TestAccPagerDutyEscalationPolicyWithTeams_Basic
--- PASS: TestAccPagerDutyEscalationPolicyWithTeams_Basic (12.92s)
=== RUN   TestAccPagerDutyEventRule_Basic
    TestAccPagerDutyEventRule_Basic: testing.go:654: Step 1 error: errors during apply:

        Error: POST API call to https://api.pagerduty.com/event_rules failed: 409 Conflict

          on /tmp/tf-test562488633/main.tf line 2:
          (source code not available)


--- FAIL: TestAccPagerDutyEventRule_Basic (5.60s)
=== RUN   TestAccPagerDutyExtension_Basic
--- PASS: TestAccPagerDutyExtension_Basic (18.29s)
=== RUN   TestAccPagerDutyMaintenanceWindow_Basic
--- PASS: TestAccPagerDutyMaintenanceWindow_Basic (17.87s)
=== RUN   TestAccPagerDutySchedule_Basic
--- PASS: TestAccPagerDutySchedule_Basic (14.97s)
=== RUN   TestAccPagerDutyScheduleOverflow_Basic
--- PASS: TestAccPagerDutyScheduleOverflow_Basic (15.24s)
=== RUN   TestAccPagerDutySchedule_BasicWeek
--- PASS: TestAccPagerDutySchedule_BasicWeek (14.16s)
=== RUN   TestAccPagerDutySchedule_Multi
--- PASS: TestAccPagerDutySchedule_Multi (9.10s)
=== RUN   TestAccPagerDutyServiceIntegration_Basic
--- PASS: TestAccPagerDutyServiceIntegration_Basic (19.86s)
=== RUN   TestAccPagerDutyServiceIntegrationGeneric_Basic
--- PASS: TestAccPagerDutyServiceIntegrationGeneric_Basic (17.95s)
=== RUN   TestAccPagerDutyService_Basic
--- PASS: TestAccPagerDutyService_Basic (19.56s)
=== RUN   TestAccPagerDutyService_AlertGrouping
--- PASS: TestAccPagerDutyService_AlertGrouping (15.13s)
=== RUN   TestAccPagerDutyService_BasicWithIncidentUrgencyRules
--- PASS: TestAccPagerDutyService_BasicWithIncidentUrgencyRules (20.09s)
=== RUN   TestAccPagerDutyService_FromBasicToCustomIncidentUrgencyRules
--- PASS: TestAccPagerDutyService_FromBasicToCustomIncidentUrgencyRules (14.27s)
=== RUN   TestAccPagerDutyService_SupportHoursChange
--- PASS: TestAccPagerDutyService_SupportHoursChange (14.55s)
=== RUN   TestAccPagerDutyTeamMembership_Basic
--- PASS: TestAccPagerDutyTeamMembership_Basic (8.24s)
=== RUN   TestAccPagerDutyTeam_Basic
--- PASS: TestAccPagerDutyTeam_Basic (9.15s)
=== RUN   TestAccPagerDutyUserContactMethodEmail_Basic
--- PASS: TestAccPagerDutyUserContactMethodEmail_Basic (13.26s)
=== RUN   TestAccPagerDutyUserContactMethodPhone_Basic
--- PASS: TestAccPagerDutyUserContactMethodPhone_Basic (13.41s)
=== RUN   TestAccPagerDutyUserContactMethodSMS_Basic
--- PASS: TestAccPagerDutyUserContactMethodSMS_Basic (13.41s)
=== RUN   TestAccPagerDutyUser_Basic
--- PASS: TestAccPagerDutyUser_Basic (10.96s)
=== RUN   TestAccPagerDutyUserWithTeams_Basic
--- PASS: TestAccPagerDutyUserWithTeams_Basic (17.49s)
FAIL
FAIL    github.com/terraform-providers/terraform-provider-pagerduty/pagerduty   513.134s
FAIL
make: *** [GNUmakefile:17: testacc] Error 1

The only failure in TestAccPagerDutyEventRule_Basic is already reported in #175.

[stmcallister]

I just started hitting the same issues! Thanks for this PR!