tests: Install python-gnupg first.

.github/workflows/ci.yml

@@ -38,6 +38,7 @@ jobs:
           sudo apt-get install -y firefox
         fi
         python -m pip install --upgrade pip
+        pip install python-gnupg
         pip install -e .[dev]
         pip install -r requirements.txt --require-hashes
     - name: Install