ci: do not require DCO job

We are going to disable this job for this repository and rely on
contributors' implicit acceptance of DCO.txt instead.

Signed-off-by: Ken Dreyer <[email protected]>

Author: ktdreyer

.github/mergify.yml

@@ -11,7 +11,6 @@ pull_request_rules:
     - label!=hold
     - label!=do-not-merge
     - label!=needs-rebase
-    - check-success=DCO
 
     # The files conditions regex should match the globs in workflow files
     # If workflow configuration files in .github/ are changed, the actionlint check must pass