Add support for reproducible builds

As per gradle [docs] add support to remove timestamps and package with same order which is required from
[reproducible] builds

[docs]: https://docs.gradle.org/current/userguide/working_with_files.html#sec:archives
[reproducible]: https://reproducible-builds.org/

Signed-off-by: Leonidas Spyropoulos <artafinde@archlinux.com>

build.gradle

@@ -88,6 +88,10 @@ allprojects {
         compileKotlin.kotlinOptions.jvmTarget = compileTestKotlin.kotlinOptions.jvmTarget = JavaVersion.VERSION_11
         compileKotlin.dependsOn ktlint
     }
+    tasks.withType(AbstractArchiveTask).configureEach {
+        preserveFileTimestamps = false
+        reproducibleFileOrder = true
+    }
 }
 
 evaluationDependsOnChildren()