Fix webapp resource lookup

pom.xml

@@ -142,7 +142,6 @@
       </resource>
       <resource>
         <directory>core/src/main/webapp</directory>
-        <targetPath>webapp</targetPath>
       </resource>
       <resource>
         <directory>src/main/resources</directory>

src/main/java/io/jenkins/plugins/localization_zh_cn/LocalizationContributorImpl.java

@@ -13,6 +13,9 @@ public class LocalizationContributorImpl extends LocalizationContributor {
     @CheckForNull
     @Override
     public URL getResource(@Nonnull String s) {
+        if (s.startsWith("/")) {
+            s = s.substring(1);
+        }
         return getClass().getClassLoader().getResource(s);
     }