Use 3.11 for Github actions

Closes #5920

Author: Pierre-Sassoulas

.github/workflows/tests.yaml

@@ -21,7 +21,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10"]
+        python-version: [3.7, 3.8, 3.9, "3.10", "3.11-dev"]
     outputs:
       python-key: ${{ steps.generate-python-key.outputs.key }}
     steps:
@@ -174,7 +174,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10"]
+        python-version: [3.7, 3.8, 3.9, "3.10", "3.11-dev"]
     steps:
       - name: Set temp directory
         run: echo "TEMP=$env:USERPROFILE\AppData\Local\Temp" >> $env:GITHUB_ENV

setup.cfg

@@ -23,6 +23,7 @@ classifiers =
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: Implementation :: PyPy
     Topic :: Software Development :: Debuggers