Fix Javadoc builds with the jsr305 dependency. (#306)

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

adapters/pom.xml

@@ -17,6 +17,11 @@
       <artifactId>moshi</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>com.google.code.findbugs</groupId>
+      <artifactId>jsr305</artifactId>
+      <scope>provided</scope>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>