Add package-info.java

error-prone-contrib/pom.xml

@@ -192,6 +192,11 @@
             <artifactId>error_prone_annotation</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.errorprone</groupId>
+            <artifactId>error_prone_annotations</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>com.google.errorprone</groupId>
             <artifactId>error_prone_check_api</artifactId>

error-prone-contrib/src/main/java/com/picnicinternational/errorprone/bugpatterns/package-info.java

@@ -0,0 +1,3 @@
+@com.google.errorprone.annotations.CheckReturnValue
+@javax.annotation.ParametersAreNonnullByDefault
+package com.picnicinternational.errorprone.bugpatterns;