DOC: README: Fix broken link in migrator
A stray space in the link for the migrator repository wasn't allowing it
to be rendered properly in markdown viewers. Remove such a space to
avoid this.
@@ -76,8 +76,7 @@ may be the better choice.
For those who have previously deployed their own registry based on the Registry
1.0 implementation and wish to deploy a Registry 2.0 while retaining images,
data migration is required. A tool to assist with migration efforts has been
-created. For more information see [docker/migrator]
-(https://github.com/docker/migrator).
+created. For more information see [docker/migrator](https://github.com/docker/migrator).
## Contribute
