Bump maven-compiler-plugin from 3.1 to 3.8.1

Bumps [maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.1 to 3.8.1.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](apache/maven-compiler-plugin@maven-compiler-plugin-3.1...maven-compiler-plugin-3.8.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

pom.xml

@@ -114,7 +114,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.1</version>
+        <version>3.8.1</version>
         <configuration>
           <source>6</source>
           <target>6</target>