Bump github.com/pb33f/libopenapi from 0.15.3 to 0.15.4 (#135)

Bumps [github.com/pb33f/libopenapi](https://github.com/pb33f/libopenapi) from 0.15.3 to 0.15.4.
- [Release notes](https://github.com/pb33f/libopenapi/releases)
- [Commits](pb33f/libopenapi@v0.15.3...v0.15.4)

---
updated-dependencies:
- dependency-name: github.com/pb33f/libopenapi
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/hashicorp/cli v1.1.6
 	github.com/hashicorp/terraform-plugin-codegen-spec v0.1.0
 	github.com/mattn/go-colorable v0.1.13
-	github.com/pb33f/libopenapi v0.15.3
+	github.com/pb33f/libopenapi v0.15.4
 	gopkg.in/yaml.v3 v3.0.1
 )
 

go.sum

@@ -102,8 +102,8 @@ github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1y
 github.com/onsi/gomega v1.17.0/go.mod h1:HnhC7FXeEQY45zxNK3PPoIUhzk/80Xly9PcubAlGdZY=
 github.com/onsi/gomega v1.19.0 h1:4ieX6qQjPP/BfC3mpsAtIGGlxTWPeA3Inl/7DtXw1tw=
 github.com/onsi/gomega v1.19.0/go.mod h1:LY+I3pBVzYsTBU1AnDwOSxaYi9WoWiqgwooUqq9yPro=
-github.com/pb33f/libopenapi v0.15.3 h1:P3D4Vnuvct3PD9ctwGxmmvniBUrEs1A3GjQcSfxjQrg=
-github.com/pb33f/libopenapi v0.15.3/go.mod h1:m+4Pwri31UvcnZjuP8M7TlbR906DXJmMvYsbis234xg=
+github.com/pb33f/libopenapi v0.15.4 h1:saAA9RZpECBcOUqkXUmDQDdKtf5/wexvAF21U6XfbQg=
+github.com/pb33f/libopenapi v0.15.4/go.mod h1:m+4Pwri31UvcnZjuP8M7TlbR906DXJmMvYsbis234xg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/complete v1.2.3 h1:NP0eAhjcjImqslEwo/1hq7gpajME0fTLTezBKDqfXqo=