Fix LICENSE link in CONTRIBUTING.md

Signed-off-by: Adam Fowler <adamfowler71@gmail.com>

Author: adam-fowler

CONTRIBUTING.md

@@ -5,7 +5,7 @@ We appreciate all contributions — whether it’s fixing bugs, improving docume
 
 ## Legal
 By submitting a pull request, you represent that you have the right to license your contribution to the community, and agree by submitting the patch
-that your contributions are licensed under the Apache 2.0 license (see [LICENSE](LICENSE)).
+that your contributions are licensed under the Apache 2.0 license (see [LICENSE](LICENSE.txt)).
 
 ## Developer Certificate of Origin