Update CONTRIBUTING.rst

Author: gonchik

CONTRIBUTING.rst

@@ -64,6 +64,7 @@ All methods based on docs from: https://developer.atlassian.com/docs/
 *  Bitbucket:
     - https://developer.atlassian.com/server/bitbucket/reference/rest-api/
     - https://developer.atlassian.com/server/bitbucket/how-tos/command-line-rest/
+    - https://developer.atlassian.com/bitbucket/api/2/reference/resource/
 * Bamboo:
     - https://docs.atlassian.com/atlassian-bamboo/REST/latest/
 * Tempo:
@@ -96,4 +97,4 @@ In addition to all the contributors we would like to thank to these companies:
 .. _Atlassian: https://www.atlassian.com/
 .. _JetBrains: http://www.jetbrains.com
 .. _PyCharm: http://www.jetbrains.com/pycharm/
-.. _Travis: https://travis-ci.org/
+.. _Travis: https://travis-ci.org/