Update build.gradle

Add osgi plugin in order to generate bundle manifest

Author: Thomas Draier

build.gradle

@@ -25,6 +25,7 @@ ext {
 
 apply plugin: 'java'
 apply plugin: 'maven'
+apply plugin: 'osgi'
 apply from: "$projectDir/gradle/publishing.gradle"
 
 repositories {
@@ -61,4 +62,4 @@ dependencies {
 task wrapper(type: Wrapper) {
     gradleVersion = '4.0'
     distributionUrl = "http://services.gradle.org/distributions/gradle-4.0-all.zip"
-}
+}