Small GH Actions optimizations

- Set `fail-fast` to false so we'll see the outcome of all the builds
- Trigger `push` only on `master` so we won't have duplicate builds

Author: cortinico

.github/workflows/pre-merge.yaml

@@ -1,9 +1,16 @@
 name: Pre Merge Checks
-on: [push, pull_request]
+on: 
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - '*'
 
 jobs:
   gradle:
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}