Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v3...v4)

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

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

.github/workflows/release-artifacts.yml

@@ -66,7 +66,7 @@ jobs:
           install: true
 
       - name: Set up docker layer caching
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: /tmp/.buildx-cache
           key: ${{ runner.os }}-buildx-${{ github.sha }}

.github/workflows/tests.yml

@@ -169,7 +169,7 @@ jobs:
       # Cribbed from
       # https://github.com/AustinScola/mypy-cache-github-action/blob/85ea4f2972abed39b33bd02c36e341b28ca59213/src/restore.ts#L10-L17
       - name: Restore/persist mypy's cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             .mypy_cache