Apply maven-publish plugin explicitly when needed
diff --git a/all/build.gradle b/all/build.gradle
index 3df9132..5cd86fe 100644
--- a/all/build.gradle
+++ b/all/build.gradle
@@ -1,4 +1,6 @@
 plugins {
+    id "maven-publish"
+
     id "com.github.kt3k.coveralls"
 }