github: use newer hg versions

Author: felipec

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        hg: [ '5.5', '5.6', '5.7', '5.8', '5.9', '6.0', '6.1', '6.2', '6.3', '6.4' ]
+        hg: [ '6.0', '6.1', '6.2', '6.3', '6.4', '6.5', '6.6', '6.7', '6.8', '6.9' ]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4