ci: fix slack notification action ref

Author: mrehan27

.github/workflows/reusable_build_sample_apps.yml

@@ -159,7 +159,7 @@ jobs:
 
       - name: Send Slack Notification for Sample App Builds
         if: ${{ always() && env.IS_PRIMARY_APP == 'true' }}
-        uses: customerio/mobile-ci-tools/github-actions/slack-notify-sample-app/v1
+        uses: customerio/mobile-ci-tools/github-actions/slack-notify-sample-app/v1@main
         with:
           build_status: ${{ job.status }}
           app_icon_emoji: ":android:"
@@ -193,4 +193,4 @@ jobs:
           issue-number: ${{ github.event.pull_request.number }}
           body: |
             * ${{ matrix.sample-app }}: Build failed. See [CI job logs](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}}) to determine the issue and try re-building.
-          edit-mode: append # append new line to the existing PR comment to build a list of all sample app builds.
+          edit-mode: append # append new line to the existing PR comment to build a list of all sample app builds.