Update reference to contributing file

Signed-off-by: Emmanuel Ferdman <[email protected]>

Author: emmanuel-ferdman

.github/ISSUE_TEMPLATE/config.yml

@@ -4,6 +4,6 @@ contact_links:
     url: https://discord.gg/7xgjhVAg6g
     about: You can ask for help here!
   - name: Want to contribute to step certificates?
-    url: https://github.com/smallstep/certificates/blob/master/docs/CONTRIBUTING.md
+    url: https://github.com/smallstep/certificates/blob/master/CONTRIBUTING.md
     about: Be sure to read contributing guidelines!