Add maven-exec-plugin info to tasks/pom.xml. (GoogleCloudPlatform#1155)

Author: dzlier-gcp

appengine-java8/tasks/pom.xml

@@ -37,7 +37,6 @@ Copyright 2018 Google LLC
   <properties>
     <maven.compiler.target>1.8</maven.compiler.target>
     <maven.compiler.source>1.8</maven.compiler.source>
-    <maven-exec-plugin.version>1.6.0</maven-exec-plugin.version>
   </properties>
 
   <dependencies>
@@ -86,7 +85,7 @@ Copyright 2018 Google LLC
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
-        <version>${maven-exec-plugin.version}</version>
+        <version>1.6.0</version>
         <configuration>
           <mainClass>com.example.task.CreateTask</mainClass>
           <cleanupDaemonThreads>false</cleanupDaemonThreads>

tasks/pom.xml

@@ -75,6 +75,17 @@ Copyright 2018 Google LLC
 
   <build>
     <sourceDirectory>src/main/java</sourceDirectory>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>1.6.0</version>
+        <configuration>
+          <mainClass>com.example.Quickstart</mainClass>
+          <cleanupDaemonThreads>false</cleanupDaemonThreads>
+        </configuration>
+      </plugin>
+    </plugins>
   </build>
 
 </project>