gradle: extend publish task to checksum output in build/repo dir

build.gradle.kts

@@ -66,3 +66,22 @@ val compileTestKotlin: KotlinCompile by tasks
 compileTestKotlin.kotlinOptions {
     jvmTarget = "1.8"
 }
+
+val sourcesJar by tasks.registering(Jar::class) {
+    classifier = "sources"
+    from(sourceSets.main.get().allSource)
+}
+
+publishing {
+    repositories {
+        maven {
+            url = uri("$buildDir/repo")
+        }
+    }
+    publications {
+        register("mavenJava", MavenPublication::class) {
+            from(components["java"])
+            artifact(sourcesJar.get())
+        }
+    }
+}