[all] Downgrade Launch4j version because the latest version has inval…

…id configuration for MacOS.

The latest version 1.7.19 depends transitively on the
net.sf.launch4j:launch4j:jar:workdir-osx Maven package, which is not on
Central. The provided package is workdir-mac.

Signed-off-by: Stéphane Galland <galland@arakhne.org>

pom.xml

@@ -583,7 +583,7 @@
 				<plugin>
 					<groupId>com.akathist.maven.plugins.launch4j</groupId>
 					<artifactId>launch4j-maven-plugin</artifactId>
-					<version>1.7.19</version>
+					<version>1.7.18</version>
 				</plugin>
 
 				<plugin>