Added missing issue links

Author: Frank Schmid

README.md

@@ -646,3 +646,9 @@ plugin when running a command or invoked by a hook.
 [link-260]: https://github.com/serverless-heaven/serverless-webpack/issues/260
 [link-264]: https://github.com/serverless-heaven/serverless-webpack/pull/264
 [link-265]: https://github.com/serverless-heaven/serverless-webpack/pull/265
+
+[link-272]: https://github.com/serverless-heaven/serverless-webpack/issues/272
+[link-278]: https://github.com/serverless-heaven/serverless-webpack/pull/278
+[link-279]: https://github.com/serverless-heaven/serverless-webpack/issues/279
+[link-276]: https://github.com/serverless-heaven/serverless-webpack/issues/276
+[link-269]: https://github.com/serverless-heaven/serverless-webpack/issues/269