Added RF v6.1.1 to the test matrix

Author: emanlove

.github/workflows/CI.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         python-version: [3.8, 3.11]  # 3.12, pypy-3.9
-        rf-version: [4.1.3, 5.0.1, 6.0.1]
+        rf-version: [4.1.3, 5.0.1, 6.0.1, 6.1.1]
 
     steps:
     - uses: actions/checkout@v3