`conflict-marker` doesn't work in Milestone page #4391

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I found conflict-marker feature quite useful. I can see conflict icon in pr page https://github.com/the-tcpdump-group/libpcap/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc+milestone%3Anext-release <img width="885" alt="conflict_marker_in_pr" src="https://user-images.githubusercontent.com/1066923/119283778-0839c300-bc79-11eb-8aad-5aac1d2e86b4.png">

but not in milestone page https://github.com/the-tcpdump-group/libpcap/milestone/1 <img width="885" alt="no_conflict_marker_in_milestone" src="https://user-images.githubusercontent.com/1066923/119283793-0c65e080-bc79-11eb-9b64-8daa372415ee.png">