bump checkoutv2 to v4 in pylint

Author: jcurtis2

.github/workflows/pylint.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         submodules: recursive
     - uses: actions/setup-python@v2