install fish in GH actions

Author: suchipi

.github/workflows/ci_tests.yml

@@ -13,5 +13,8 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      - name: Install dependencies
+        run: sudo apt-get install -y fish
+
       - name: Run tests
         run: ./in-docker.sh 'npm install && npm run build && npm test'