update to Java 11

build.gradle

@@ -14,10 +14,7 @@ apply from: project(":nshmp-lib").file("gradle/git-hooks.gradle")
 apply from: project(":nshmp-lib").file("gradle/spotbugs.gradle")
 apply from: project(":nshmp-lib").file("gradle/spotless.gradle")
 
-java {
-  sourceCompatibility = JavaVersion.VERSION_11
-  targetCompatibility = JavaVersion.VERSION_11
-}
+sourceCompatibility = JavaVersion.VERSION_11
 compileJava.options.encoding = "UTF-8"
 
 repositories {