Add missing version tags
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
+ <version>3.6.1</version>
<configuration>
<optimize>true</optimize>
<showDeprecation>true</showDeprecation>
<plugin>
<groupId>com.yahoo.vespa</groupId>
<artifactId>bundle-plugin</artifactId>
+ <version>${vespa_version}</version>
<extensions>true</extensions>
</plugin>
</plugins>
