Bump org.apache.maven:maven-core in /build-parent/maven-plugin

Bumps [org.apache.maven:maven-core](https://github.com/apache/maven) from 3.6.3 to 3.8.1.
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.6.3...maven-3.8.1)

---
updated-dependencies:
- dependency-name: org.apache.maven:maven-core
  dependency-type: direct:production
...

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

build-parent/maven-plugin/pom.xml

@@ -85,7 +85,7 @@
         <dependency>
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-core</artifactId>
-            <version>3.6.3</version>
+            <version>3.8.1</version>
             <type>jar</type>
         </dependency>