Activate maven-enforcer-plugin by default

[marcwrobel]

Maven complains that maven-enforcer-plugin is not activated when running mvn versions:display-plugin-updates with Maven 3.9.

955 [INFO] Error stacktraces are turned on.
1034 [INFO] Scanning for projects...
1490 [INFO] 
1490 [INFO] ------------------------< fr.marcwrobel:parent >------------------------
1490 [INFO] Building parent 3.1.0-SNAPSHOT
1490 [INFO]   from pom.xml
1490 [INFO] --------------------------------[ pom ]---------------------------------
1498 [INFO] 
1499 [INFO] --- versions:2.15.0:display-plugin-updates (default-cli) @ parent ---
2188 [INFO] 
2188 [INFO] All plugins with a version specified are using the latest versions.
2188 [INFO] 
2188 [INFO] All plugins have a version specified.
2188 [INFO] 
2188 [WARNING] Project does not define minimum Maven version required for build, default is: 3.2.5
2188 [INFO] Plugins require minimum Maven version of: 3.5.4
2188 [INFO] 
2188 [ERROR] Project does not define required minimum version of Maven.
2188 [ERROR] Update the pom.xml to contain maven-enforcer-plugin to
2188 [ERROR] force the Maven version which is needed to build this project.
2188 [ERROR] See https://maven.apache.org/enforcer/enforcer-rules/requireMavenVersion.html
2188 [ERROR] Using the minimum version of Maven: 3.5.4
2188 [INFO] 
2189 [INFO] ------------------------------------------------------------------------
2189 [INFO] BUILD SUCCESS
2189 [INFO] ------------------------------------------------------------------------
2190 [INFO] Total time:  1.217 s

It would be a good idea to activate it by default.