do not run release on pr (#113)

.github/workflows/go.yml

@@ -5,8 +5,6 @@ on:
     branches: [ master ]
   pull_request:
     types: [assigned, opened, synchronize, reopened]
-  release:
-    types: [ released ]
 
 jobs:
 
@@ -49,5 +47,7 @@ jobs:
     - name: create release
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      if: github.ref == 'refs/heads/master'
       run: |
         gh release create -d --generate-notes v$NBGV_SimpleVersion
+        gh release list | grep Draft | tail -n +3 | cut -f 1 | xargs -r -L 1 gh release delete --yes