Bump golang.org/x/mod from 0.8.0 to 0.9.0

Bumps [golang.org/x/mod](https://github.com/golang/mod) from 0.8.0 to 0.9.0.
- [Release notes](https://github.com/golang/mod/releases)
- [Commits](golang/mod@v0.8.0...v0.9.0)

---
updated-dependencies:
- dependency-name: golang.org/x/mod
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/phayes/checkstyle v0.0.0-20170904204023-bfd46e6a821d
 	github.com/t-yuki/gocover-cobertura v0.0.0-20180217150009-aaee18c8195c
-	golang.org/x/mod v0.8.0
+	golang.org/x/mod v0.9.0
 	gopkg.in/yaml.v2 v2.4.0
 )
 

go.sum

@@ -8,8 +8,8 @@ github.com/phayes/checkstyle v0.0.0-20170904204023-bfd46e6a821d h1:CdDQnGF8Nq9oc
 github.com/phayes/checkstyle v0.0.0-20170904204023-bfd46e6a821d/go.mod h1:3OzsM7FXDQlpCiw2j81fOmAwQLnZnLGXVKUzeKQXIAw=
 github.com/t-yuki/gocover-cobertura v0.0.0-20180217150009-aaee18c8195c h1:+aPplBwWcHBo6q9xrfWdMrT9o4kltkmmvpemgIjep/8=
 github.com/t-yuki/gocover-cobertura v0.0.0-20180217150009-aaee18c8195c/go.mod h1:SbErYREK7xXdsRiigaQiQkI9McGRzYMvlKYaP3Nimdk=
-golang.org/x/mod v0.8.0 h1:LUYupSeNrTNCGzR/hVBk2NHZO4hXcVaW1k4Qx7rjPx8=
-golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.9.0 h1:KENHtAZL2y3NLMYZeHY9DW8HW8V+kQyJsY/V9JlKvCs=
+golang.org/x/mod v0.9.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=