Update python versions in tests (#13)

* Update python versions in tests
Add up to and including 3.13
* Update flake8 for Python 3.12
* Actually 3.10 is minimum for all codegens under development

Author: ponyisi

.github/workflows/ci.yaml

@@ -13,13 +13,13 @@ jobs:
   test:
     strategy:
       matrix:
-        python-version: ['3.7','3.8','3.9','3.10']
+        python-version: ['3.10','3.11','3.12','3.13']
     runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@master
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install poetry