SC-6662 update README to use v3 of actions

Author: bogdanakushnir

README.md

@@ -41,7 +41,7 @@ jobs:
   sonarcloud:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         # Disabling shallow clone is recommended for improving relevancy of reporting
         fetch-depth: 0