github: fix integration tests in CI

Signed-off-by: Simon Deziel <[email protected]>

.github/workflows/tests.yml

@@ -87,15 +87,19 @@ jobs:
     - name: Install dependencies
       run: |
         set -x
-        pip install --upgrade pip tox codecov
+        python3 -m venv venv
+        . ./venv/bin/activate
+        ./venv/bin/pip install --require-virtualenv --upgrade pip tox codecov
 
     - name: Coverage
       run: |
+        . ./venv/bin/activate
         tox -e coverage
         codecov
 
     - name: Integration
       run: |
+        . ./venv/bin/activate
         integration/run-integration-tests
 
   publish: