fix(ci): give the 55m unit shards the 60m the startup guard requires

The startup guard's row-wise matrix pairing fix exposed three unit shard
rows (caching-local, proxy-extras, enterprise-package) still capped at
job-timeout-minutes 55, under the 60 the guard's contract needs: up to
35m of setup plus 5m of runner overhead would preempt a 20m pytest
budget. Every PR's code-quality check is red on the base until these
rows match the 60 the sibling rows already use

.github/workflows/test-unit.yml

@@ -211,7 +211,7 @@ jobs:
             workers: 2
             reruns: 2
             timeout-minutes: 20
-            job-timeout-minutes: 55
+            job-timeout-minutes: 60
 
           - shard: proxy-extras
             artifact-name: proxy-extras
@@ -219,7 +219,7 @@ jobs:
             workers: 2
             reruns: 2
             timeout-minutes: 20
-            job-timeout-minutes: 55
+            job-timeout-minutes: 60
 
           - shard: enterprise-package
             artifact-name: enterprise-package
@@ -227,7 +227,7 @@ jobs:
             workers: 4
             reruns: 2
             timeout-minutes: 20
-            job-timeout-minutes: 55
+            job-timeout-minutes: 60
 
           - shard: responses-caching-types
             artifact-name: responses-caching-types