Ignore duplicates in sourcesJar

.gitlab-ci.yml

 image: eclipse-temurin:8
 
 variables:
-  GRADLE_ARGS: --no-daemon --warning-mode=all
+  GRADLE_ARGS: --no-daemon --stacktrace --warning-mode=all
   GRADLE_USER_HOME: "$CI_PROJECT_DIR/.gradle"
 
 cache:

tlatools/build.gradle

@@ -53,6 +53,8 @@ if (project.hasProperty('ossrhUsername') && project.hasProperty('ossrhPassword')
 	task sourcesJar(type: Jar) {
 		classifier = 'sources'
 		from sourceSets.main.allSource
+		// Ignore duplicates because the same directory is used for sources and resources.
+		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 	}
 
 	artifacts {