deps: declare go 1.18 in go.mod

This updates the go.{mod,sum} files to declare a version of Go that supports
module graph pruning. The change allows consuming projects to avoid picking
up dependencies on modules that ghw only uses for testing or for its CLI.

Fixes #328

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

Author: whereswaldon

go.mod

@@ -1,20 +1,23 @@
 module github.com/jaypipes/ghw
 
-go 1.15
+go 1.18
 
 require (
 	github.com/StackExchange/wmi v1.2.1
 	github.com/ghodss/yaml v1.0.0
+	github.com/jaypipes/pcidb v1.0.0
+	github.com/pkg/errors v0.9.1
+	github.com/spf13/cobra v0.0.3
+	howett.net/plist v1.0.0
+)
+
+require (
 	github.com/go-ole/go-ole v1.2.6 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
-	github.com/jaypipes/pcidb v1.0.0
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
-	github.com/pkg/errors v0.9.1
-	github.com/spf13/cobra v0.0.3
 	github.com/spf13/pflag v1.0.2 // indirect
 	golang.org/x/sys v0.0.0-20220319134239-a9b59b0215f8 // indirect
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	howett.net/plist v1.0.0
 )

go.sum

@@ -15,7 +15,6 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/mitchellh/go-homedir v1.0.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=