build(deps): bump github.com/docker/distribution (#994)

Bumps [github.com/docker/distribution](https://github.com/docker/distribution) from 2.7.1+incompatible to 2.8.0+incompatible.
- [Release notes](https://github.com/docker/distribution/releases)
- [Commits](https://github.com/docker/distribution/compare/v2.7.1...v2.8.0)

---
updated-dependencies:
- dependency-name: github.com/docker/distribution
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/andreaskoch/go-fswatch v1.0.0
 	github.com/containerd/continuity v0.2.0 // indirect
 	github.com/docker/cli v20.10.12+incompatible
-	github.com/docker/distribution v2.7.1+incompatible
+	github.com/docker/distribution v2.8.0+incompatible
 	github.com/docker/docker v20.10.12+incompatible
 	github.com/go-git/go-billy/v5 v5.3.1
 	github.com/go-git/go-git/v5 v5.4.2