maven-plugins: Raise base maven version to 3.8.1

The old 3.3.9 version is from 2015 and its components have known CVEs.

Signed-off-by: BJ Hargrave <hargrave@us.ibm.com>

org.eclipse.transformer.parent/pom.xml

@@ -32,7 +32,7 @@
 		<assertj.version>3.26.3</assertj.version>
 		<xmlunit.version>2.10.0</xmlunit.version>
 		<bytebuddy.version>1.15.0</bytebuddy.version>
-		<maven.target.version>3.3.9</maven.target.version>
+		<maven.target.version>3.8.1</maven.target.version>
 		<shrinkwrap.version>1.2.6</shrinkwrap.version>
 		<!-- Reproducible build -->
 		<project.build.outputTimestamp>1980-02-01T00:00:00Z</project.build.outputTimestamp>
@@ -528,7 +528,7 @@ SPDX-License-Identifier: ${project.licenses[0].name}
 			<dependency>
 				<groupId>org.apache.maven</groupId>
 				<artifactId>maven-aether-provider</artifactId>
-				<version>${maven.target.version}</version>
+				<version>3.3.9</version>
 				<scope>test</scope>
 			</dependency>
 			<dependency>