Update POM to use newer version of enforcer plugin (#100)

I ran into an issue when attempting to build the accumulo-examples repo.
Running ./bin/build resulted in the a maven-enforcer-plugin error:

ERROR] Failed to execute goal
org.apache.maven.plugins:maven-enforcer-plugin:1.4.1:enforce
(enforce-java-version) on project accumulo-examples: Execution
enforce-java-version of goal
org.apache.maven.plugins:maven-enforcer-plugin:1.4.1:enforce failed: An
API incompatibility was encountered while executing
org.apache.maven.plugins:maven-enforcer-plugin:1.4.1:enforce:
java.lang.ExceptionInInitializerError: null
[ERROR] -----------------------------------------------------
[ERROR] realm =
plugin>org.apache.maven.plugins:maven-enforcer-plugin:1.4.1
[ERROR] strategy =
org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
[ERROR] urls[0] =
file:/home/mark/.m2/repository/org/apache/maven/plugins/maven-enforcer-plugin/1.4.1/maven-enforcer-plugin-1.4.1.jar
[ERROR] urls[1] =
file:/home/mark/.m2/repository/backport-util-concurrent/backport-util-concurrent/3.1/backport-util-concurrent-3.1.jar
[ERROR] urls[2] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-interpolation/1.11/plexus-interpolation-1.11.jar
[ERROR] urls[3] =
file:/home/mark/.m2/repository/org/slf4j/slf4j-jdk14/1.5.6/slf4j-jdk14-1.5.6.jar
[ERROR] urls[4] =
file:/home/mark/.m2/repository/org/slf4j/jcl-over-slf4j/1.5.6/jcl-over-slf4j-1.5.6.jar
[ERROR] urls[5] =
file:/home/mark/.m2/repository/org/apache/maven/reporting/maven-reporting-api/2.2.1/maven-reporting-api-2.2.1.jar
[ERROR] urls[6] =
file:/home/mark/.m2/repository/org/apache/maven/doxia/doxia-sink-api/1.1/doxia-sink-api-1.1.jar
[ERROR] urls[7] =
file:/home/mark/.m2/repository/org/apache/maven/doxia/doxia-logging-api/1.1/doxia-logging-api-1.1.jar
[ERROR] urls[8] =
file:/home/mark/.m2/repository/commons-cli/commons-cli/1.2/commons-cli-1.2.jar
[ERROR] urls[9] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-interactivity-api/1.0-alpha-4/plexus-interactivity-api-1.0-alpha-4.jar
[ERROR] urls[10] =
file:/home/mark/.m2/repository/org/sonatype/plexus/plexus-sec-dispatcher/1.3/plexus-sec-dispatcher-1.3.jar
[ERROR] urls[11] =
file:/home/mark/.m2/repository/org/sonatype/plexus/plexus-cipher/1.4/plexus-cipher-1.4.jar
[ERROR] urls[12] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-utils/3.0.22/plexus-utils-3.0.22.jar
[ERROR] urls[13] =
file:/home/mark/.m2/repository/commons-lang/commons-lang/2.3/commons-lang-2.3.jar
[ERROR] urls[14] =
file:/home/mark/.m2/repository/org/apache/maven/enforcer/enforcer-api/1.4.1/enforcer-api-1.4.1.jar
[ERROR] urls[15] =
file:/home/mark/.m2/repository/org/apache/maven/enforcer/enforcer-rules/1.4.1/enforcer-rules-1.4.1.jar
[ERROR] urls[16] =
file:/home/mark/.m2/repository/org/apache/maven/shared/maven-common-artifact-filters/1.4/maven-common-artifact-filters-1.4.jar
[ERROR] urls[17] =
file:/home/mark/.m2/repository/org/beanshell/bsh/2.0b4/bsh-2.0b4.jar
[ERROR] urls[18] =
file:/home/mark/.m2/repository/org/apache/maven/shared/maven-dependency-tree/2.2/maven-dependency-tree-2.2.jar
[ERROR] urls[19] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-component-annotations/1.5.5/plexus-component-annotations-1.5.5.jar
[ERROR] urls[20] =
file:/home/mark/.m2/repository/org/eclipse/aether/aether-util/0.9.0.M2/aether-util-0.9.0.M2.jar
[ERROR] urls[21] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-i18n/1.0-beta-6/plexus-i18n-1.0-beta-6.jar
[ERROR] urls[22] =
file:/home/mark/.m2/repository/org/apache/maven/plugin-testing/maven-plugin-testing-harness/1.3/maven-plugin-testing-harness-1.3.jar
[ERROR] urls[23] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-archiver/2.2/plexus-archiver-2.2.jar
[ERROR] urls[24] =
file:/home/mark/.m2/repository/org/codehaus/plexus/plexus-io/2.0.4/plexus-io-2.0.4.jar
[ERROR] urls[25] =
file:/home/mark/.m2/repository/junit/junit/4.11/junit-4.11.jar
[ERROR] urls[26] =
file:/home/mark/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar
[ERROR] Number of foreign imports: 1
[ERROR] import: Entry[import  from realm ClassRealm[maven.api, parent:
null]]
[ERROR]
[ERROR] -----------------------------------------------------
[ERROR] : begin 0, end 3, length 2

OS was Ubuntu 21.10.

Updating the examples pom to use version 3.0.0-M3 resolved the error.
This also brings the examples repo up to date with the version of the
plugin used by the main Accumulo project.

pom.xml

@@ -153,6 +153,11 @@
           <artifactId>maven-dependency-plugin</artifactId>
           <version>3.3.0</version>
         </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-enforcer-plugin</artifactId>
+          <version>3.0.0-M3</version>
+        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>