Fix typo (dart-lang/package_config#149)

pkgs/package_config/lib/src/package_config.dart

diff --git a/pkgs/package_config/lib/src/package_config.dart b/pkgs/package_config/lib/src/package_config.dart
index c00ac67..048555f 100644
--- a/pkgs/package_config/lib/src/package_config.dart
+++ b/pkgs/package_config/lib/src/package_config.dart
@@ -26,7 +26,7 @@
   /// is expected, but none have been specified or found.
   static const PackageConfig empty = SimplePackageConfig.empty();
 
-  /// Creats a package configuration with the provided available [packages].
+  /// Creates a package configuration with the provided available [packages].
   ///
   /// The packages must be valid packages (valid package name, valid
   /// absolute directory URIs, valid language version, if any),