Update PR title

Author: Mustafa Zengin

.github/workflows/create-beta-pull-request.yml

@@ -38,7 +38,7 @@ jobs:
       shell: bash
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        MESSAGE_TITLE: Generated models and request builders using Typewriter
+        MESSAGE_TITLE: Generated beta models using Typewriter
         MESSAGE_BODY: "This pull request was automatically created by the GitHub Action, **${{github.workflow}}**. \n\n The commit hash is _${{github.sha}}_. \n\n **Important** Check for unexpected deletions or changes in this PR. See [beta_metadata.xml](https://github.com/microsoftgraph/msgraph-metadata/blob/master/beta_metadata.xml) for metadata changes. \n\n Make sure the version number is incremented in /src/Core/GraphConstants.php. Compare the version against the latest release on [packagist.org](https://packagist.org/packages/microsoft/microsoft-graph) and update the version in src/Core/GraphConstants. \n\n cc: @darrelmiller"
         REVIEWERS: peombwa,ddyett,zengin,nikithauc,baywet
         ASSIGNEDTO: MIchaelMainer