Adding a condition for null

Author: kishore7snehil

.github/actions/get-release-notes/action.yml

@@ -34,7 +34,7 @@ runs:
             state: 'all',
             head: `${process.env.REPO_OWNER}:release/${process.env.VERSION}`,
           });
-          core.setOutput('RELEASE_NOTES', pulls[0].body || '');
+          core.setOutput('RELEASE_NOTES', pulls[0]?.body ?? '');
       env:
         GITHUB_TOKEN: ${{ inputs.token }}
         REPO_OWNER: ${{ inputs.repo_owner }}