Update flatpak_release.yml

Author: NikolasK-source

.github/workflows/flatpak_release.yml

@@ -1,7 +1,6 @@
 on:
   push:
     branches: [release]
-  pull_request:
 name: Flatpak_release
 jobs:
   flatpak:
@@ -17,4 +16,4 @@ jobs:
       with:
         bundle: modbus-tcp-client-shm.flatpak
         manifest-path: network.koesling.modbus-tcp-client-shm.yml
-        cache-key: flatpak-builder-${{ github.sha }}
+        cache-key: flatpak-builder-${{ github.sha }}