set reasonable timeout for pull-kubernetes-e2e-ec2 (1h)

these are normally completing in ~30m, I've seen a 4h timeout that is clearly a buged run, no point in hanging for 4h on a PR

Author: BenTheElder

config/jobs/kubernetes/sig-cloud-provider/aws/ec2-e2e.yaml

@@ -19,7 +19,7 @@ presubmits:
     cluster: eks-prow-build-cluster
     decorate: true
     decoration_config:
-      timeout: 4h
+      timeout: 1h
     extra_refs:
       - org: kubernetes-sigs
         repo: provider-aws-test-infra