Update README.md

[ci skip]

Author: exogen

README.md

@@ -268,7 +268,7 @@ When npm installs from a Git repository or any other non-package location, it
 will first prepare the directory as if it were publishing a package. This
 includes respecting the `.npmignore` file and `files` field in `package.json`,
 which means that `postinstall` scripts may be executed with a subset of the
-files you may need to run your build step. Thus, in order for `postinstall-build`
+files you need to run your build step. Thus, in order for `postinstall-build`
 to work, you should **not** ignore the source files or any necessary
 configuration (for example, `.babelrc`).