🚨 Use cache in docs.yml

Author: ronisbr

.github/workflows/docs.yml

@@ -15,6 +15,7 @@ jobs:
       - uses: julia-actions/setup-julia@v2
         with:
           version: '1'
+      - uses: julia-actions/cache@v2
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-docdeploy@releases/v1
         env: