use pip instead of make in static-checks CI

This commit will change the way how the test requirements are installed
in CI during static-checks.

Signed-off-by: Jan Richter <jarichte@redhat.com>

.github/workflows/ci.yml

@@ -22,7 +22,8 @@ jobs:
       - name: Allow git to operate on directory checked out by GH Actions
         run: git config --global --add safe.directory `pwd`
       - name: Installing Avocado development dependencies
-        run: make requirements-dev
+        run: python3 -m pip install --user -r requirements-dev.txt
+        continue-on-error: true
       - name: Installing Avocado in develop mode
         run: python3 setup.py develop --user
       - name: Run static checks