Bump actions/cache from 2 to 3 (#876)

Bumps [actions/cache](https://github.com/actions/cache) from 2 to 3.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v2...v3)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/docs-retro.yml

@@ -19,7 +19,7 @@ jobs:
           toolchain: stable
 
       - name: Cache Dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/.cargo
           key: cargo-cache-${{ hashFiles('**/Cargo.lock') }}