Only allow release on manual trigger

.github/workflows/release.yml

@@ -1,7 +1,4 @@
 on:
-  push:
-    branches:
-      - master
   workflow_dispatch:
     inputs:
       version:
@@ -21,4 +18,4 @@ jobs:
         who-to-greet: 'Mona the Octocat wants to release ${{ github.event.inputs.version }}'
     # Use the output from the `hello` step
     - name: Get the output time
-      run: echo "The time was ${{ steps.hello.outputs.time }}"
+      run: echo "The time was ${{ steps.hello.outputs.time }}"