Update 02-libraries.md: typo

doc/02-libraries.md

@@ -124,7 +124,7 @@ Once you have a vcs repository (version control system, e.g. git) containing a
 example we will publish the `acme/hello-world` library on GitHub under
 `github.com/composer/hello-world`.
 
-Now, To test installing the `acme/hello-world` package, we create a new
+Now, to test installing the `acme/hello-world` package, we create a new
 project locally. We will call it `acme/blog`. This blog will depend on
 `acme/hello-world`, which in turn depends on `monolog/monolog`. We can
 accomplish this by creating a new `blog` directory somewhere, containing a