Cache Qt for ResInsight

.github/workflows/main.yml

@@ -18,12 +18,18 @@ jobs:
         uses: actions/checkout@v1
         with:
           submodules: true
+      - name: Cache Qt
+        id: cache-qt
+        uses: actions/cache@v1
+        with:
+          path: ../Qt
+          key: ${{ runner.os }}-QtCache
       - name: Install Qt
-        uses: jurplel/install-qt-action@v2.5.0
+        uses: jurplel/install-qt-action@v2
         with:
           version: 5.9.9
           modules: qtscript 
-          mirror: 'http://mirrors.ocf.berkeley.edu/qt/'
+          cached: ${{ steps.cache-qt.outputs.cache-hit }}
       - name: Install Python dependencies
         run: |
           python -m pip install --upgrade pip