Updates default assignees for topic requests

Author: vulder

.github/ISSUE_TEMPLATE/topic-proposal.md

@@ -3,7 +3,7 @@ name: Topic proposal
 about: Describes a topic that should be considered by SG20 for education guidelines
 title: "[TOPIC-REQUEST]"
 labels: Needs triaging
-assignees: BobSteagall, cjdb, jcvw
+assignees: vulder, jcvw
 
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