ci: adds cache and build on PR

Author: asm0dey

.github/workflows/build.yml

@@ -1,6 +1,6 @@
 name: Java CI
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
@@ -12,5 +12,13 @@ jobs:
         uses: actions/setup-java@v1
         with:
           java-version: 1.8
+      - name: Cache Maven packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.m2
+          key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-m2
       - name: Build with Maven
-        run: mvn -B package verify --file pom.xml
+        run: mvn -B package --file pom.xml
+
+# vim: ts=2:sts=2:sw=2:expandtab