Remove getStackName() method

lib/plugins/aws/provider/awsProvider.js

@@ -121,21 +121,6 @@ class AwsProvider {
     }
   }
 
-  /**
-   * Deprecated method. Moved to naming.js
-   * Kept here for backward compatibility
-   */
-  getStackName(stage) {
-    const warningMessage = [
-      'Deprecation Notice: provider.getStackName() method is deprecated.',
-      ' Please reference the naming.js file instead: ',
-      ' ex. naming.getStackName();',
-    ].join('');
-
-    this.serverless.cli.log(warningMessage);
-    return `${this.serverless.service.service}-${stage}`;
-  }
-
   request(service, method, params) {
     const that = this;
     const credentials = that.getCredentials();