try caching precompilation

Author: jumerckx

.github/workflows/CI.yml

@@ -93,6 +93,8 @@ jobs:
           #   libReactant: packaged
           #   version: '1.10'
           #   test_group: integration
+        TMPDIR: ${{ github.workspace }}/tmp
+        JULIA_DEPOT_PATH: "${{ github.workspace }}/.julia_depot:"
     steps:
       - name: Set TMPDIR
         # We have to use `${GITHUB_WORKSPACE}` instead of `github.workspace` because GitHub
@@ -104,6 +106,17 @@ jobs:
       - name: Create TMPDIR
         run: |
           mkdir -p ${{ env.TMPDIR }}
+      - name: Create Julia Depot Directory
+        run: |
+            mkdir -p ${{ github.workspace }}/.julia_depot
+      - name: Cache Julia Depot
+        uses: actions/cache@v4
+        with:
+            path: ${{ github.workspace }}/.julia_depot
+            key: julia-depot-${{ runner.os }}-${{ runner.arch }}-${{ matrix.version }}-${{ hashFiles('**/Project.toml', '**/Manifest.toml') }}
+            restore-keys: |
+                julia-depot-${{ runner.os }}-${{ runner.arch }}-${{ matrix.version }}-
+                julia-depot-${{ runner.os }}-${{ runner.arch }}-
       - uses: julia-actions/setup-julia@v2
         if: ${{ ! matrix.assertions }}
         with: