chore: ignore package-lock.json and remove its references (#1252)

Author: snitin315

.github/CONTRIBUTING.md

@@ -79,7 +79,7 @@ In case you are suggesting a new feature, we will match your idea with our curre
 
 ## Running Tests
 
-### Using npm
+### Using yarn
 
 -   Run all the tests with:
 
@@ -128,7 +128,7 @@ The [.editorconfig](https://github.com/webpack/webpack-cli/blob/master/.editorco
 
 This is a multi-package repository and dependencies are managed using [lerna](https://lerna.js.org/)
 
-> If you are adding or updating any dependency, please commit the updated `package-lock.json` file.
+> If you are adding or updating any dependency, please commit the updated `yarn.lock` file.
 
 ## Branching Model
 

.gitignore

@@ -38,6 +38,9 @@ lerna-debug.log
 # Yeoman file
 .yo-rc.json
 
+# package-lock file
+package-lock.json
+
 # source maps of docs
 docs/**/*.map
 junit.xml