Cache conda dependencies for Github workflow execution

.github/workflows/build.yml

@@ -18,17 +18,27 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+      - name: Cache conda
+        uses: actions/cache@v2
+        env:
+          # Increase this value to reset cache if etc/example-environment.yml has not changed
+          CACHE_NUMBER: 0
+        with:
+          path: ~/conda_pkgs_dir
+          key:
+            ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}-${{
+            hashFiles('etc/example-environment.yml') }}
       - uses: conda-incubator/setup-miniconda@v2
         with:
           activate-environment: test
           environment-file: environment.yml
           python-version: 3.8
           auto-activate-base: false
+          use-only-tar-bz2: true
       - name: Conda Info
         run: |
           conda info
           conda list
       - name: Run Pytest
         run: |
-            conda install pytest
             python -m pytest