Run Flake8 CI on Ubuntu 22.04. (#25)

Co-authored-by: repo-helper[bot] <74742576+repo-helper[bot]@users.noreply.github.com>

Author: repo-helper[bot]

.github/workflows/flake8.yml

@@ -16,7 +16,7 @@ permissions:
 jobs:
   Run:
     name: "Flake8"
-    runs-on: "ubuntu-20.04"
+    runs-on: "ubuntu-22.04"
 
     steps:
       - name: Checkout 🛎️