Bump julia-actions/cache from 2 to 3 (#796)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
-      - uses: julia-actions/cache@v2
+      - uses: julia-actions/cache@v3
       - name: Set NaN-safe mode preference
         run: |
           open(joinpath(pwd(), "Project.toml"), "a") do io
@@ -60,7 +60,7 @@ jobs:
       - uses: julia-actions/setup-julia@v2
         with:
           version: '1'
-      - uses: julia-actions/cache@v2
+      - uses: julia-actions/cache@v3
       - name: Set up environment
         run: julia --project=docs -e 'using Pkg; Pkg.instantiate()'
       - name: Run doctests