build(deps): bump org.apache.maven:maven-core

Bumps [org.apache.maven:maven-core](https://github.com/apache/maven) from 3.0 to 3.8.1.
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.0...maven-3.8.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

bigtable-test/hbase-minicluster-maven-plugin/pom.xml

@@ -19,7 +19,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
         <!-- do not upgrade this, we are target all of maven 3 -->
-        <target-maven.version>3.0</target-maven.version>
+        <target-maven.version>3.8.1</target-maven.version>
         <!-- This can be updated freely -->
         <maven-plugin-tools.version>3.10.2</maven-plugin-tools.version>
     </properties>