Chore: Downgrade kin-openapi to v0.112.0

[xnyo]

What this PR does / why we need it:

Downgrade kin-openapi to v0.112.0.

(Bumped by dependabot from v0.94.0 on c7f540c)

Versions from v0.113.0+ cause the following issue when trying to build Grafana core due to a dependency conflict:

╰─❯ make gen-go
generate code from .cue files
go generate ./pkg/plugins/plugindef
# github.com/deepmap/oapi-codegen/pkg/codegen
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/schema.go:86:27: undefined: openapi3.ExtensionProps
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/schema.go:311:38: invalid operation: schema.AdditionalProperties != nil (mismatched types openapi3.AdditionalProperties and untyped nil)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/schema.go:312:47: cannot use schema.AdditionalProperties (variable of type openapi3.AdditionalProperties) as *openapi3.SchemaRef value in argument to GenerateGoSchema
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/merge_schemas.go:215:32: invalid operation: s1.AdditionalProperties != nil (mismatched types openapi3.AdditionalProperties and untyped nil)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/merge_schemas.go:218:32: invalid operation: s2.AdditionalProperties != nil (mismatched types openapi3.AdditionalProperties and untyped nil)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/operations.go:129:22: pd.Spec.ExtensionProps undefined (type *openapi3.Parameter has no field or method ExtensionProps)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/operations.go:130:57: pd.Spec.ExtensionProps undefined (type *openapi3.Parameter has no field or method ExtensionProps)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/operations.go:833:32: param.Spec.ExtensionProps undefined (type *openapi3.Parameter has no field or method ExtensionProps)
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/prune.go:38:21: cannot use &swagger.Components (value of type **openapi3.Components) as *openapi3.Components value in argument to walkComponents
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/prune.go:147:20: cannot use ref.Value.AdditionalProperties (variable of type openapi3.AdditionalProperties) as *openapi3.SchemaRef value in argument to walkSchemaRef
/home/giuseppe/go/pkg/mod/github.com/spinillos/oapi-codegen@v1.12.5-0.20230206122001-6a05ca88e18e/pkg/codegen/schema.go:312:47: too many errors
pkg/plugins/plugindef/plugindef.go:12: running "go": exit status 1
make: *** [Makefile:73: gen-cue] Error 1

Which issue(s) this PR fixes:

Special notes for your reviewer:

[andresmgot]

is @spinillos aware of this? we should update that forked library it seems