fix: add codecov coverage upload (#316)

Author: igdianov

.github/workflows/build.yml

@@ -20,11 +20,16 @@ jobs:
         java: [ '8', '11' ]
     steps:
     - uses: actions/checkout@v3
+
     - name: Set up JDK 11
       uses: actions/setup-java@v3
       with:
         java-version: ${{ matrix.java }}      
         distribution: 'adopt'
         cache: maven
+
     - name: Build with Maven
       run: mvn -B -ntp package
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v3