Fix archive name

Author: st4lk

lib/inject.js

@@ -95,7 +95,7 @@ function injectAllRequirements() {
       .map(func => {
         if (func.module !== '.') {
           const artifact = func.package.artifact;
-          const newArtifact = path.join('.serverless', `${func.module-func.name}.zip`);
+          const newArtifact = path.join('.serverless', `${func.module}-${func.name}.zip`);
           func.package.artifact = newArtifact;
           return moveModuleUp(artifact, newArtifact, func.module).then(
             () => func