Bump github.com/golangci/golangci-lint from 1.30.0 to 1.31.0 in /tools (

#343)

* Bump github.com/golangci/golangci-lint from 1.30.0 to 1.31.0 in /tools

Bumps [github.com/golangci/golangci-lint](https://github.com/golangci/golangci-lint) from 1.30.0 to 1.31.0.
- [Release notes](https://github.com/golangci/golangci-lint/releases)
- [Changelog](https://github.com/golangci/golangci-lint/blob/master/CHANGELOG.md)
- [Commits](golangci/golangci-lint@v1.30.0...v1.31.0)

Signed-off-by: dependabot[bot] <support@github.com>

* Auto-fix go.sum changes in dependent modules

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: dependabot[bot] <dependabot[bot]@users.noreply.github.com>

tools/go.mod

@@ -4,6 +4,6 @@ go 1.13
 
 require (
 	github.com/client9/misspell v0.3.4
-	github.com/golangci/golangci-lint v1.30.0
-	golang.org/x/tools v0.0.0-20200724022722-7017fd6b1305
+	github.com/golangci/golangci-lint v1.31.0
+	golang.org/x/tools v0.0.0-20200812195022-5ae4c3c160a0
 )