[PULL_REQUEST_TEMPLATE.md] Fix typo

.github/PULL_REQUEST_TEMPLATE.md

@@ -11,7 +11,7 @@
 - [ ] [Searched](https://github.com/rg3/youtube-dl/search?q=is%3Apr&type=Issues) the bugtracker for similar pull requests
 
 ### In order to be accepted and merged into youtube-dl each piece of code must be in public domain or released under [Unlicense](http://unlicense.org/). Check one of the following options:
-- [ ] I am the original original author of this code and I am willing to release it under [Unlicense](http://unlicense.org/)
+- [ ] I am the original author of this code and I am willing to release it under [Unlicense](http://unlicense.org/)
 - [ ] I am not the original author of this code but it is in public domain or released under [Unlicense](http://unlicense.org/) (provide reliable evidence)
 
 ### What is the purpose of your *pull request*?