Add checkstyle to forge-runtime

forge-runtime/build.gradle

@@ -1,6 +1,7 @@
 plugins {
 	id 'java'
 	id 'maven-publish'
+	id 'checkstyle'
 	id 'com.github.johnrengelman.shadow'
 	id 'org.cadixdev.licenser'
 }
@@ -61,6 +62,11 @@ license {
 	exclude '**/loom/inject/mixin/MixinIntermediaryDevRemapper.java'
 }
 
+checkstyle {
+	configFile = rootProject.checkstyle.configFile
+	toolVersion = rootProject.checkstyle.toolVersion
+}
+
 publishing {
 	publications {
 		maven(MavenPublication) {