Add individual build checks for master and not-master branches

.github/workflows/build.yml

@@ -1,6 +1,9 @@
 name: Build
 
-on: push
+on:
+  push:
+    branches:
+      - master
 
 jobs:
   build:

.github/workflows/build_others.yml

@@ -0,0 +1,20 @@
+name: Other build checks
+
+on:
+  push:
+    branches:
+      - '!master'
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - name: set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Build with Gradle
+        run: ./gradlew build