put .buildinfo into the sources.jar too

* then this would also be in the sources.jar in maven central
diff --git a/build.gradle.kts b/build.gradle.kts
index e9da10a..fc37519 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -105,6 +105,12 @@
     from(files("LICENSE", "NOTICE")) {
         into("META-INF")
     }
+
+    // Depend on the createBuildInfo task and include the generated file
+    dependsOn(createBuildInfo)
+    from(File(project.buildDir, "tmp/buildinfo")) {
+        include(".buildinfo")
+    }
 }
 
 tasks.javadocJar.configure {