Merge pull request #1893 from henchbot/repo2docker_bump

Author: betatim

mybinder/values.yaml

@@ -118,7 +118,7 @@ binderhub:
         - ^(git|https?)%3A%2F%2Fnotabug.org%2FulslcuRux3Y%2F.*
     BinderHub:
       use_registry: true
-      build_image: jupyter/repo2docker:2021.03.0-11.g0eb7260
+      build_image: jupyter/repo2docker:2021.03.0-15.g73ab48a
       per_repo_quota: 100
       per_repo_quota_higher: 200
       build_memory_limit: "3G"