Add CodeCov GitHub action and badge. (#339)

* Add CodeCov GitHub action and badge.

* Change comment behavior and exclude sdk-tests.

.codecov.yaml

@@ -0,0 +1,6 @@
+ignore:
+  - examples
+  - sdk-tests
+comment:
+  # Delete old comment and post new one for new coverage information.
+  behavior: new

.github/workflows/build.yml

@@ -98,6 +98,8 @@ jobs:
       run: mvn compile -q
     - name: Unit tests
       run: mvn test -q
+    - name: Codecov
+      uses: codecov/codecov-action@v1
     - name: Install jars
       run: mvn install -q
     - name: Integration tests

README.md

@@ -2,6 +2,7 @@
 
 [![Build Status](https://github.com/dapr/java-sdk/workflows/Build/badge.svg?event=push&branch=master)](https://github.com/dapr/java-sdk/actions?workflow=Build)
 [![Gitter](https://badges.gitter.im/Dapr/java-sdk.svg)](https://gitter.im/Dapr/java-sdk?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+[![codecov](https://codecov.io/gh/dapr/java-sdk/branch/master/graph/badge.svg)](https://codecov.io/gh/dapr/java-sdk)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
 This is the Dapr SDK for Java, including the following features:

pom.xml

@@ -76,6 +76,25 @@
 
   <build>
     <plugins>
+      <plugin>
+	<groupId>org.jacoco</groupId>
+	<artifactId>jacoco-maven-plugin</artifactId>
+	<version>0.8.6</version>
+	<executions>
+	  <execution>
+	    <goals>
+	      <goal>prepare-agent</goal>
+	    </goals>
+	  </execution>
+	  <execution>
+	    <id>report</id>
+	    <phase>test</phase>
+	    <goals>
+	      <goal>report</goal>
+	    </goals>
+	  </execution>
+	</executions>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-gpg-plugin</artifactId>
@@ -191,6 +210,11 @@
 
   <reporting>
     <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>cobertura-maven-plugin</artifactId>
+        <version>2.7</version>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-project-info-reports-plugin</artifactId>