Bump github.com/sigstore/protobuf-specs from 0.2.1 to 0.3.0

Bumps [github.com/sigstore/protobuf-specs](https://github.com/sigstore/protobuf-specs) from 0.2.1 to 0.3.0.
- [Release notes](https://github.com/sigstore/protobuf-specs/releases)
- [Changelog](https://github.com/sigstore/protobuf-specs/blob/main/CHANGELOG.md)
- [Commits](sigstore/protobuf-specs@v0.2.1...v0.3.0)

---
updated-dependencies:
- dependency-name: github.com/sigstore/protobuf-specs
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -11,7 +11,7 @@ require (
  github.com/google/certificate-transparency-go v1.1.7
  github.com/in-toto/in-toto-golang v0.9.0
  github.com/secure-systems-lab/go-securesystemslib v0.8.0
- github.com/sigstore/protobuf-specs v0.2.1
+ github.com/sigstore/protobuf-specs v0.3.0
  github.com/sigstore/rekor v1.3.5
  github.com/sigstore/sigstore v1.8.2
  github.com/sigstore/timestamp-authority v1.2.2

go.sum

@@ -256,8 +256,8 @@ github.com/sergi/go-diff v1.3.1 h1:xkr+Oxo4BOQKmkn/B9eMK0g5Kg/983T9DqqPHwYqD+8=
 github.com/sergi/go-diff v1.3.1/go.mod h1:aMJSSKb2lpPvRNec0+w3fl7LP9IOFzdc9Pa4NFbPK1I=
 github.com/shibumi/go-pathspec v1.3.0 h1:QUyMZhFo0Md5B8zV8x2tesohbb5kfbpTi9rBnKh5dkI=
 github.com/shibumi/go-pathspec v1.3.0/go.mod h1:Xutfslp817l2I1cZvgcfeMQJG5QnU2lh5tVaaMCl3jE=
-github.com/sigstore/protobuf-specs v0.2.1 h1:KIoM7E3C4uaK092q8YoSj/XSf9720f8dlsbYwwOmgEA=
-github.com/sigstore/protobuf-specs v0.2.1/go.mod h1:xPqQGnH/HllKuZ4VFPz/g+78epWM/NLRGl7Fuy45UdE=
+github.com/sigstore/protobuf-specs v0.3.0 h1:E49qS++llp4psM+3NNVEb+C4AD422bT9VkOQIPrNLpA=
+github.com/sigstore/protobuf-specs v0.3.0/go.mod h1:ynKzXpqr3dUj2Xk9O/5ZUhjnpi0F53DNi5AdH6pS3jc=
 github.com/sigstore/rekor v1.3.5 h1:QoVXcS7NppKY+rpbEFVHr4evGDZBBSh65X0g8PXoUkQ=
 github.com/sigstore/rekor v1.3.5/go.mod h1:CWqOk/fmnPwORQmm7SyDgB54GTJizqobbZ7yOP1lvw8=
 github.com/sigstore/sigstore v1.8.2 h1:0Ttjcn3V0fVQXlYq7+oHaaHkGFIt3ywm7SF4JTU/l8c=