Show Maven stack traces on errors in GH CI

Author: garydgregory

.github/workflows/maven.yml

@@ -49,4 +49,4 @@ jobs:
         distribution: 'temurin'
         java-version: ${{ matrix.java }}
     - name: Build with Maven
-      run: mvn --show-version --batch-mode --no-transfer-progress
+      run: mvn --errors --show-version --batch-mode --no-transfer-progress