Bump github.com/getkin/kin-openapi from 0.67.0 to 0.68.0

Bumps [github.com/getkin/kin-openapi](https://github.com/getkin/kin-openapi) from 0.67.0 to 0.68.0.
- [Release notes](https://github.com/getkin/kin-openapi/releases)
- [Commits](getkin/kin-openapi@v0.67.0...v0.68.0)

---
updated-dependencies:
- dependency-name: github.com/getkin/kin-openapi
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

go.mod

@@ -3,7 +3,7 @@ module github.com/tufin/oasdiff
 go 1.15
 
 require (
-	github.com/getkin/kin-openapi v0.67.0
+	github.com/getkin/kin-openapi v0.68.0
 	github.com/stretchr/testify v1.7.0
 	github.com/yuin/goldmark v1.4.0
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect

go.sum

@@ -1,8 +1,8 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/getkin/kin-openapi v0.67.0 h1:FGVL6Rs2ZWx/RrWdoRfqw74mrkClHOg3rW6knMk7VqQ=
-github.com/getkin/kin-openapi v0.67.0/go.mod h1:7Yn5whZr5kJi6t+kShccXS8ae1APpYTW6yheSwk8Yi4=
+github.com/getkin/kin-openapi v0.68.0 h1:MRucmVSXEUCmFj6fXgC4eL0i37XTGS0EKhknv8bqZD0=
+github.com/getkin/kin-openapi v0.68.0/go.mod h1:7Yn5whZr5kJi6t+kShccXS8ae1APpYTW6yheSwk8Yi4=
 github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/go-openapi/jsonpointer v0.19.5 h1:gZr+CIYByUqjcgeLXnQu2gHYQC9o73G2XUeOFYEICuY=