Document MVN_CMD as an alternative to MVN_CMD_DIR and mvnw

Author: famod

FAQ.adoc

@@ -20,7 +20,8 @@ NOTE: Since version 3.0.3
 
 Since the version 1.14 of the Docker Pipeline plugin, `withMaven` requires to
 
-* Either prepend the `MVN_CMD_DIR` environment variable to the `PATH` environment variable in every `sh` step that invokes `mvn` (e.g. `sh 'export PATH=$MVN_CMD_DIR:$PATH && mvn clean deploy`).
+* Either prepend the `MVN_CMD_DIR` environment variable to the `PATH` environment variable in every `sh` step that invokes `mvn` (e.g. `sh 'export PATH=$MVN_CMD_DIR:$PATH && mvn clean deploy'`).
+* Or call the generated script directly via `MVN_CMD` (e.g. `sh '$MVN_CMD clean deploy'`)
 * Or use Takari's Maven Wrapper (e.g. `sh './mvnw clean deploy'`)
 
 If omitted, the Maven settings file and Mven global settings file will not be injected in the Maven execution.