Update and rename pull-requests.yml to build-pr.yml

Author: frode-carlsen

.github/workflows/build-pr.yml

@@ -0,0 +1,32 @@
+name: Pull request bygg
+
+on: 
+  pull_request:
+    paths-ignore:
+      - '**.md'
+      - '**.MD'
+      - '.gitignore'
+      - 'LICENCE'
+      - 'CODEOWNERS'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: '11.x'
+      - name: Set cache key
+        run: |
+          echo "CACHE_KEY=$(expr $(date +%V) - 1 + 1)-${{ github.event.pull_request.number }}" >> $GITHUB_ENV
+          echo "PREVIOUS_CACHE_KEY=$(expr $(date +%V) - 1 + 1)" >> $GITHUB_ENV
+      - uses: actions/cache@v2
+        with:
+          path: ~/.m2
+          key: ${{ runner.os }}-maven-${{ env.CACHE_KEY }}
+          restore-keys: |
+            ${{ runner.os }}-maven-${{ env.PREVIOUS_CACHE_KEY }}
+      
+      - name: Build
+        run: mvn verify