second attempt at catching stale PRs

The first one didn't fire, despite there being 3 PRs that should
have matched. This one tries to match the queue failure itself
instead of checking for lack of activity.

.github/mergify.yml

@@ -54,12 +54,14 @@ pull_request_rules:
       - '#changes-requested-reviews-by=0'
       # oy
       # lifted these from branch protection imports
+      - check-success=whitespace
       - check-success=fourmolu
       - check-success=hlint
       - check-success=Meta checks
       - check-success=Doctest Cabal
       - check-success=Validate post job
       - check-success=Bootstrap post job
+      - check-success=Check sdist post job
       - 'check-success=docs/readthedocs.org:cabal'
 
   # label when Mergify didn't trigger a merge automatically
@@ -75,16 +77,19 @@ pull_request_rules:
       - -merged
       - '#approved-reviews-by>=2'
       - '#changes-requested-reviews-by=0'
-      - updated-at<4 days ago
       - label=merge delay passed
+      - label!=waiting too long
+      - 'check-failure~=^Rule: Put pull requests in the '
       # oy
       # lifted these from branch protection imports
+      - check-success=whitespace
       - check-success=fourmolu
       - check-success=hlint
       - check-success=Meta checks
       - check-success=Doctest Cabal
       - check-success=Validate post job
       - check-success=Bootstrap post job
+      - check-success=Check sdist post job
       - 'check-success=docs/readthedocs.org:cabal'
 
   # rebase+merge strategy