README: update with regards to bootstrap version update

sivaraam · sivaraam · commit dd67a649d5ab · 2018-06-24T16:16:24.000+05:30
diff --git a/README.md b/README.md
@@ -4,4 +4,4 @@ This is the landing page for the [Wikimedia Commons Mobile App](https://github.c
 
 ## Contributing
 
-Contributions are welcome. Please make sure your changes work on small screens. Currently Boostrap v4 alpha is being used.
+Contributions are welcome. Please make sure your changes work on small screens. Currently Boostrap v4.1 is being used.

Original file line number	Diff line number	Diff line change
`@@ -4,4 +4,4 @@ This is the landing page for the [Wikimedia Commons Mobile App](https://github.c`
`4`	`4`
`5`	`5`	`## Contributing`
`6`	`6`
`7`		`-Contributions are welcome. Please make sure your changes work on small screens. Currently Boostrap v4 alpha is being used.`
	`7`	`+Contributions are welcome. Please make sure your changes work on small screens. Currently Boostrap v4.1 is being used.`