Update github CI to include python 3.13

Include 3.13 and use latest ubuntu image

Signed-off-by: Wayne Sun <gsun@redhat.com>

Author: waynesun09

.github/workflows/pull_request.yml

@@ -8,12 +8,10 @@ on:
 jobs:
   codechecks:
     name: Code Quality
-    # The last image version support python3.6, latest have removed it
-    # Still need python3.6 for EPEL8
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8, 3.9, "3.10", "3.11", "3.12"]
+        python-version: [3.8, 3.9, "3.10", "3.11", "3.12", "3.13"]
     steps:
       - name: Checkout Pylero
         uses: actions/checkout@v3