[BUILD] add gatherArtifacts task to automate release process

gradle/release-tasks.gradle

@@ -139,6 +139,36 @@ task extractReleaseNotesNext {
         }
     }
 }
+task gatherArtifacts(type: Copy) {
+    from('build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*'
+    }
+    from('picocli-codegen/build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*', '*javadoc*'
+    }
+    from('picocli-groovy/build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*', '*javadoc*'
+    }
+    from('picocli-shell-jline2/build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*', '*javadoc*'
+    }
+    from('picocli-shell-jline3/build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*', '*javadoc*'
+    }
+    from('picocli-spring-boot-starter/build/libs/') {
+        include '*.jar', '*.asc'
+        exclude '*test*', '*sources*', '*javadoc*'
+    }
+    from('build/distributions/') {
+        include '*.zip'
+    }
+    into 'build/artifacts'
+}
 
 /*
 Release procedure:
@@ -171,7 +201,9 @@ Release procedure:
 
 18. Log in to GitHub, go to https://github.com/remkop/picocli/releases
 19. Click the new tag, click Edit button, update title and release notes (copy from RELEASE-NOTES.md)
-20. Upload picocli-$version.jar and picocli-all$version.zip to GitHub
+20. ./gradlew gatherArtifacts
+21. explorer C:\Users\remko\IdeaProjects\picocli3\build\artifacts
+22. Upload all files in build/artifacts to GitHub
 
 
 (When releasing from branch)