Docs - README.md - Fix Good First Issue Link

Summary:
<!--
Thank you for sending the PR! We appreciate you spending the time to work on these changes.

Help us understand your motivation by explaining why you decided to make this change.

You can learn more about contributing to React Native here: http://facebook.github.io/react-native/docs/contributing.html

Happy contributing!

-->

I was reading the README and I noticed the link to [Good first issue](https://github.com/facebook/react-native/labels/Good%20first%20issue) was pointing to a wrong label.

N/A

[DOCS][BUGFIX][README.md] - Fix beginners friendly bug link in README.md

<!--
Help reviewers and the release process by writing your own release notes

**INTERNAL and MINOR tagged notes will not be included in the next version's final release notes.**

  CATEGORY
[----------]        TYPE
[ CLI      ]   [-------------]      LOCATION
[ DOCS     ]   [ BREAKING    ]   [-------------]
[ GENERAl  ]   [ BUGFIX      ]   [-{Component}-]
[ INTERNAL ]   [ ENHANCEMENT ]   [ {File}      ]
[ IOS      ]   [ FEATURE     ]   [ {Directory} ]   |-----------|
[ ANDROID  ]   [ MINOR       ]   [ {Framework} ] - | {Message} |
[----------]   [-------------]   [-------------]   |-----------|

[CATEGORY] [TYPE] [LOCATION] - MESSAGE

 EXAMPLES:

 [IOS] [BREAKING] [FlatList] - Change a thing that breaks other things
 [ANDROID] [BUGFIX] [TextInput] - Did a thing to TextInput
 [CLI] [FEATURE] [local-cli/info/info.js] - CLI easier to do things with
 [DOCS] [BUGFIX] [GettingStarted.md] - Accidentally a thing/word
 [GENERAL] [ENHANCEMENT] [Yoga] - Added new yoga thing/position
 [INTERNAL] [FEATURE] [./scripts] - Added thing to script that nobody will see
-->
Closes https://github.com/facebook/react-native/pull/16523

Differential Revision: D6138904

Pulled By: hramos

fbshipit-source-id: 42800feca9445156eac7d479ee8548c4a427f156

README.md

@@ -58,7 +58,7 @@ Read our [contributing guide](https://facebook.github.io/react-native/docs/contr
 
 ### Beginner Friendly Bugs
 
-We have a list of [beginner friendly issues](https://github.com/facebook/react-native/labels/Good%20First%20Task) to help you get your feet wet in the React Native codebase and familiar with our contribution process. This is a great place to get started.
+We have a list of [beginner friendly issues](https://github.com/facebook/react-native/labels/Good%20First%20Issue) to help you get your feet wet in the React Native codebase and familiar with our contribution process. This is a great place to get started.
 
 ## License