workaround new diff-coverage

Author: tomato42

.github/workflows/ci.yml

@@ -337,9 +337,15 @@ jobs:
       - name: Lint the code
         # pylint doesn't work on 2.6: https://bitbucket.org/logilab/pylint/issue/390/py26-compatiblity-broken
         if: ${{ matrix.python-version != '2.6' }}
+        env:
+          PYTHON_VERSION: ${{ matrix.python-version }}
         run: |
+          opt=""
+          if ! [[ $PYTHON_VERSION == 2.6 || $PYTHON_VERSION == 2.7 || $PYTHON_VERSION == 3.3 || $PYTHON_VERSION == 3.4 || $PYTHON_VERSION == 3.5 ]]; then
+              opt="--compare-branch origin/master"
+          fi
           pylint --msg-template="{path}:{line}: [{msg_id}({symbol}), {obj}] {msg}" tlslite > pylint_report.txt || :
-          diff-quality --violations=pylint --fail-under=90 pylint_report.txt
+          diff-quality $opt --violations=pylint --fail-under=90 pylint_report.txt
       - name: Verify that intermediate commits are testable
         if: ${{ github.event.pull_request }}
         env: