Use spring-release-actions/announce-on-gchat

Uses common action for GChat release announcements

* Respond to Feedback

This commit restores the original conditional, given that
secrets are not accessible in conditionals. It also relies
on the announce-to-gchat project name defaut

---------

Signed-off-by: Josh Cummings <3627351+jzheaux@users.noreply.github.com>

Author: jzheaux

.github/workflows/spring-finalize-release.yml

@@ -122,8 +122,10 @@ jobs:
 
       - name: Announce Release in Chat
         if: env.CHAT_WEBHOOK_URL
-        run: |
-          curl -X POST '${{ env.CHAT_WEBHOOK_URL }}' -H 'Content-Type: application/json' -d '{ text: "${{ github.event.repository.name }}-announcing `${{ inputs.milestone }}`"}'
+        uses: spring-io/spring-release-actions/announce-on-gchat@0.0.1
+        with:
+          gchat-webhook-url: ${{ env.CHAT_WEBHOOK_URL }}
+          version: ${{ inputs.milestone }}
         env:
           CHAT_WEBHOOK_URL: ${{ secrets.SPRING_RELEASE_CHAT_WEBHOOK_URL }}
 
@@ -137,4 +139,4 @@ jobs:
 #          payload: |
 #            {
 #              "text": "${{ github.event.repository.name }}-announcing `${{ inputs.milestone }}`"
-#            }
+#            }