define JPMS module names

_This change is similar to Incendo/cloud#787

Author: Djaytan

gradle/build-logic/src/main/kotlin/cloud-discord.base-conventions.gradle.kts

@@ -30,3 +30,11 @@ dependencies {
     testImplementation(libs.mockito.jupiter)
     testImplementation(libs.truth)
 }
+
+tasks {
+    jar {
+        manifest {
+            attributes("Automatic-Module-Name" to "%s.%s".format(project.group, project.name.replace('-', '.')))
+        }
+    }
+}