build(deps): bump github.com/opencontainers/image-spec

Bumps [github.com/opencontainers/image-spec](https://github.com/opencontainers/image-spec) from 1.1.0-rc5 to 1.1.0-rc.6.
- [Release notes](https://github.com/opencontainers/image-spec/releases)
- [Changelog](https://github.com/opencontainers/image-spec/blob/main/RELEASES.md)
- [Commits](opencontainers/image-spec@v1.1.0-rc5...v1.1.0-rc6)

---
updated-dependencies:
- dependency-name: github.com/opencontainers/image-spec
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

go.mod

@@ -4,6 +4,6 @@ go 1.20
 
 require (
 	github.com/opencontainers/go-digest v1.0.0
-	github.com/opencontainers/image-spec v1.1.0-rc5
+	github.com/opencontainers/image-spec v1.1.0-rc.6
 	golang.org/x/sync v0.6.0
 )

go.sum

@@ -1,6 +1,6 @@
 github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
-github.com/opencontainers/image-spec v1.1.0-rc5 h1:Ygwkfw9bpDvs+c9E34SdgGOj41dX/cbdlwvlWt0pnFI=
-github.com/opencontainers/image-spec v1.1.0-rc5/go.mod h1:X4pATf0uXsnn3g5aiGIsVnJBR4mxhKzfwmvK/B2NTm8=
+github.com/opencontainers/image-spec v1.1.0-rc.6 h1:Kv1Dp8IuQevyC6QTol7CYJWdQMfpRUhmJ1yntMKiJR0=
+github.com/opencontainers/image-spec v1.1.0-rc.6/go.mod h1:W4s4sFTMaBeK1BQLXbG4AdM2szdn85PY75RI83NrTrM=
 golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
 golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=