Bump github.com/pb33f/libopenapi from 0.21.5 to 0.21.8 (#233)

Bumps [github.com/pb33f/libopenapi](https://github.com/pb33f/libopenapi) from 0.21.5 to 0.21.8.
- [Release notes](https://github.com/pb33f/libopenapi/releases)
- [Commits](pb33f/libopenapi@v0.21.5...v0.21.8)

---
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>

Author: dependabot[bot]

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/hashicorp/cli v1.1.7
 	github.com/hashicorp/terraform-plugin-codegen-spec v0.2.0
 	github.com/mattn/go-colorable v0.1.14
-	github.com/pb33f/libopenapi v0.21.5
+	github.com/pb33f/libopenapi v0.21.8
 	gopkg.in/yaml.v3 v3.0.1
 )
 

go.sum

@@ -57,8 +57,8 @@ github.com/mitchellh/copystructure v1.2.0/go.mod h1:qLl+cE2AmVv+CoeAwDPye/v+N2HK
 github.com/mitchellh/reflectwalk v1.0.0/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
 github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zxSIeXaQ=
 github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
-github.com/pb33f/libopenapi v0.21.5 h1:oqYgK2hzFU3cVp1T6mUu9mwh7vVYcQaBHXsdSCn/q4U=
-github.com/pb33f/libopenapi v0.21.5/go.mod h1:Gc8oQkjr2InxwumK0zOBtKN9gIlv9L2VmSVIUk2YxcU=
+github.com/pb33f/libopenapi v0.21.8 h1:Fi2dAogMwC6av/5n3YIo7aMOGBZH/fBMO4OnzFB3dQA=
+github.com/pb33f/libopenapi v0.21.8/go.mod h1:Gc8oQkjr2InxwumK0zOBtKN9gIlv9L2VmSVIUk2YxcU=
 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=