mergify: Change docker-images check more explicit

The previous check was never matching because mergify was not being given the
name of the matrix job, it is only given the realized name for each matrix
instance. We also need to spell each matrix permuation we care about instead of
`check-success~=docker-image` because mergify will happily merge once the first
image build succeeds, it has not way to know it needs to wait for all of them.

Signed-off-by: Manuel Mendez <mmendez@equinix.com>

.github/mergify.yml

@@ -3,7 +3,9 @@ queue_rules:
     conditions:
       # Conditions to get out of the queue (= merged)
       - check-success=DCO
-      - check-success=docker-images
+      - check-success~=docker-images.*tink-cli
+      - check-success~=docker-images.*tink-server
+      - check-success~=docker-images.*tink-worker
       - check-success=validation
 
 pull_request_rules:
@@ -14,7 +16,9 @@ pull_request_rules:
       - "#changes-requested-reviews-by=0"
       - "#review-requested=0"
       - check-success=DCO
-      - check-success=docker-images
+      - check-success~=docker-images.*tink-cli
+      - check-success~=docker-images.*tink-server
+      - check-success~=docker-images.*tink-worker
       - check-success=validation
       - label!=do-not-merge
       - label=ready-to-merge