Add comment to release documentation warning users to not run 02-sour…

…ce.sh until the Release GH Actions workflow is finished

docs/source/developers/release.rst

@@ -201,7 +201,10 @@ Build source and binaries and submit them
 
     # Build the source release tarball and create Pull Request with verification tasks
     #
-    # Note that you need to have GitHub CLI installed to run this script.
+    # NOTE: Do not run this script until the "Release" GitHub Actions workflow - triggered by 
+    #       pushing the release candidate tag - has finished.
+    #
+    # NOTE: You need to have GitHub CLI installed to run this script.
     dev/release/02-source.sh <version> <rc-number>
 
     # Submit binary tasks using crossbow, the command will output the crossbow build id