actions: build release snapshot only on main and tags

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

.github/workflows/ci.yaml

@@ -119,6 +119,7 @@ jobs:
     - name: Import GPG key
       id: import_gpg
       uses: crazy-max/ghaction-import-gpg@v4
+      if: startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main'
       with:
         gpg_private_key: ${{ secrets.GPG_KEY }}
         passphrase: ${{ secrets.GPG_PASSWORD }}
@@ -127,6 +128,7 @@ jobs:
       run: make build-snapshot
 
     - name: Release Snapshot
+      if: startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main'
       env:
         GITHUB_TOKEN: ${{ secrets.REPOSITORIES_ACCESS_TOKEN }}
         GPG_PASSWORD: ${{ secrets.GPG_PASSWORD }}