Geo: Increase HTTP read timeout of proxy requests to 60 s

For large pushes over SSH, we observed that it took some time for the secondary server to hear back from the primary server after the POST request to the /api/v4/geo/proxy_git_push/ssh/push endpoint. The client would give up on the request and fail the entire push.

To give more room for these pushes to go through, bump the timeout from the original 10 seconds to 60 seconds.