add cache

Author: baggepinnen

.github/workflows/CI.yml

@@ -27,6 +27,7 @@ jobs:
       - name: Set debug env
         run: export JULIA_DEBUG="loading"
       - uses: actions/[email protected]
+      - uses: julia-actions/cache@v1
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}