fall back to ubuntu-20.04

.github/workflows/tests.yml

@@ -37,7 +37,7 @@ jobs:
 
   js:
     name: JavaScript
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python
@@ -48,8 +48,6 @@ jobs:
         cache-dependency-path: |-
           **/setup.cfg
           **/requirements*.txt
-    - name: Install apt dependencies
-      run: sudo apt-get install -y firefox geckodriver
     - name: Get browser version
       run: firefox --version && geckodriver --version
     - name: Install python dependencies