Use disperse validate action.

.github/workflows/disperse.yml

@@ -11,14 +11,4 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - name: Set up Python
-        uses: actions/setup-python@v2
-      - name: Install dependencies
-        run: |
-          sudo apt install protobuf-compiler
-      - name: Install disperse
-        run: |
-          pip install git+https://github.com/jelmer/disperse
-      - name: Validate disperse.conf
-        run: |
-          PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python disperse validate .
+      - uses: jelmer/action-disperse-validate@v1