Bump julia-actions/cache from 2 to 3

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

---
updated-dependencies:
- dependency-name: julia-actions/cache
  dependency-version: '3'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/CI.yml

@@ -29,7 +29,7 @@ jobs:
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: julia-actions/cache@v2
+      - uses: julia-actions/cache@v3
       - uses: julia-actions/julia-buildpkg@v1
 
       - name: Run tests

.github/workflows/ExportPluto.yml

@@ -28,7 +28,7 @@ jobs:
           show-versioninfo: true
 
       - name: Cache Julia artifacts & such
-        uses: julia-actions/cache@v2
+        uses: julia-actions/cache@v3
         with:
           cache-registries: "true"