Declare jsr305 as a dependency.

It was a choice in 9252212887f6991b0ef08d40352bede7d96a37a9 to
leave it out as it wasn't needed at runtime, but a change in
165f8d82b1278bee6233c47f7deebcb8e5126165 added a runtime
dependency on the javax.annotation.Nonnull annotation.

Change-Id: I9f38e53d958be8968dd7908a855cb4c46ba2a59e
diff --git a/maven/poms/gwt/gwt-dev/pom-template.xml b/maven/poms/gwt/gwt-dev/pom-template.xml
index 02e3d52..0e39df0 100644
--- a/maven/poms/gwt/gwt-dev/pom-template.xml
+++ b/maven/poms/gwt/gwt-dev/pom-template.xml
@@ -15,6 +15,10 @@
 
     <dependencies>
         <dependency>
+            <groupId>com.google.code.findbugs</groupId>
+            <artifactId>jsr305</artifactId>
+        </dependency>
+        <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
         </dependency>
diff --git a/maven/poms/gwt/pom-template.xml b/maven/poms/gwt/pom-template.xml
index 3538218..2ee0ca8 100644
--- a/maven/poms/gwt/pom-template.xml
+++ b/maven/poms/gwt/pom-template.xml
@@ -133,6 +133,11 @@
                 <artifactId>tapestry</artifactId>
                 <version>4.0.2</version>
             </dependency>
+            <dependency>
+                <groupId>com.google.code.findbugs</groupId>
+                <artifactId>jsr305</artifactId>
+                <version>1.3.9</version>
+            </dependency>
             <!-- For DevMode / JUnitShell (transitive dependency on jetty-server for CodeServer) -->
             <dependency>
                 <groupId>org.eclipse.jetty</groupId>