Update CI and toxfile to use new group structure

.github/workflows/ci.yaml

@@ -5,9 +5,11 @@ on:
     types: ["opened", "synchronize"]
   push:
     branches: ["devel"]
+env:
+  POETRY_VERSION: 1.4.1
 jobs:
   Test:
-    name: Test with Python ${{ matrix.python.version }}
+    name: Python ${{ matrix.python.version }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -20,6 +22,8 @@ jobs:
             toxenv: py39
           - version: "3.10"
             toxenv: py310
+          - version: "3.11"
+            toxenv: py311
       fail-fast: true
     steps:
       - name: Checkout