Update jupyterhub/configurable-http-proxy Docker tag to v4.5.1

This MR contains the following updates:

Package	Type	Update	Change
jupyterhub/configurable-http-proxy	ironbank-docker	patch	4.5.0 -> 4.5.1
jupyterhub/configurable-http-proxy		patch	4.5.0 -> 4.5.1
jupyterhub/configurable-http-proxy	stage	patch	4.5.0 -> 4.5.1

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