Update checkout action version (#50)

Author: bharatr21

.github/steps/5-add-action-to-workflow-file.md

@@ -32,7 +32,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: ha-ha
         uses: ./.github/actions/joke-action
 ```