fix(deps): update dependency dev.sigstore:protobuf-specs to v0.3.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
dev.sigstore:protobuf-specs	0.3.0 -> 0.3.1

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Release Notes

sigstore/protobuf-specs (dev.sigstore:protobuf-specs)

### [`v0.3.1`](https://togithub.com/sigstore/protobuf-specs/blob/HEAD/CHANGELOG.md#031) - Added client configuration message for signing ([#​277](https://togithub.com/sigstore/protobuf-specs/pull/277)) - Added a new format for the media type that is compatible with OCI registries ([#​279](https://togithub.com/sigstore/protobuf-specs/pull/279)) - Added events.proto for Ruby package ([#​264](https://togithub.com/sigstore/protobuf-specs/pull/264)) - Targeted Node16 for Typescript package ([#​230](https://togithub.com/sigstore/protobuf-specs/pull/230)) ##### Changed - Docs: Removed timestamp from checkpoint ([#​247](https://togithub.com/sigstore/protobuf-specs/pull/247)) - Remove EXPERIMENTAL prefix from LMS schemes ([#​214](https://togithub.com/sigstore/protobuf-specs/pull/214)) ##### Fixed - Docs: Clarified trust anchor in chain [https://togithub.com/sigstore/protobuf-specs/pull/210](https://togithub.com/sigstore/protobuf-specs/pull/245)f-specs/pull/245\))

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