ci: enable caching of Julia depots for all workflows

This should speed up workflow runs (at least on subsequent builds for
the same PR/branch) and is recommended by the `julia-buildpkg`
action[^1].

[^1]: https://github.com/bauglir/Kroki.jl/actions/runs/8798251759

.github/workflows/CI.yml

@@ -32,6 +32,7 @@ jobs:
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
+      - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1

.github/workflows/CodeFormattingCheck.yml

@@ -11,11 +11,11 @@ jobs:
   code-format-check:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with:
           version: '1.10'
-
-      - uses: actions/checkout@v4
+      - uses: julia-actions/cache@v1
       - name: Install JuliaFormatter and format
         run: |
           julia  -e 'using Pkg; Pkg.add(PackageSpec(name="JuliaFormatter", version="1.0.53"))'

.github/workflows/CompatHelper.yml

@@ -12,6 +12,7 @@ jobs:
       - uses: julia-actions/setup-julia@v2
         with:
           version: '1.10'
+      - uses: julia-actions/cache@v1
       - name: Install CompatHelper
         run: julia -e 'using Pkg; Pkg.add("CompatHelper")'
       - name: Update Dependencies

.github/workflows/Documentation.yml

@@ -18,6 +18,7 @@ jobs:
       - uses: julia-actions/setup-julia@v2
         with:
           version: '1.10'
+      - uses: julia-actions/cache@v1
       - name: Install dependencies
         run: |
           julia --project=docs -e '