Fix a typo in the readme (#333)

Author: maciejmyslinski

README.md

@@ -645,7 +645,7 @@ A predicate to determine whether or not the `initialValues` prop has changed. Us
 
 #### `keepDirtyOnReinitialize?: boolean`
 
-[See the 🏁 Final Form docs on `keepDirtyOnReinitialize`](https://github.com/final-form/final-form##keepdirtyonreinitialize-boolean).
+[See the 🏁 Final Form docs on `keepDirtyOnReinitialize`](https://github.com/final-form/final-form#keepdirtyonreinitialize-boolean).
 
 #### `mutators?: { [string]: Mutator }`