Fix Javadoc builds with the jsr305 dependency.

Because multiple modules share a package we need to share the dependency on
everything in package-info.java.

okhttp-testing-support/pom.xml

@@ -23,5 +23,10 @@
       <artifactId>okhttp</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>com.google.code.findbugs</groupId>
+      <artifactId>jsr305</artifactId>
+      <scope>provided</scope>
+    </dependency>
   </dependencies>
 </project>