Support new /internal/post-receive API endpoint

Closes gitaly#522

See merge request !163

Support old versions of ruby without a monotonic clock

Closes #69

See merge request !161

Fix SSH support for Git for Windows v2.14

Closes gitlab-ce#36028

See merge request !159

Git For Windows 2.14 has a patch that changes `git-upload-pack` to `git upload-pack`.
To make this work for gitlab-shell, just map this to `git-upload-pack`.

Closes gitlab-org/gitlab-ce#36028

Support unhiding of all refs via Gitaly

See merge request !153

Bump redis-rb library to 3.3.3

See merge request !151

Fix SSH key and known_hosts support

Closes #100

See merge request !156

Bump gitaly-proto to v0.23.0

See merge request !155

Implement SSH authentication support in Ruby

Closes #95

See merge request !154

Optimize gitlab-projects by deferring the loading of gitlab_reference_counter

See merge request !149

Bump gitaly-proto version to 0.20.0

See merge request !152

Support unhiding of all refs for Geo Nodes

Closes gitlab-ee#2959

See merge request !150

By default, we hide certain refs (e.g. keep-around/XXX) to save user
download time. We need to preserve these references on secondary Geo
nodes to have a true copy.

Loading gitlab_reference_counter loads gitlab_net, which adds an
additional 100-200 ms of time. That file pulls in a vendored Redis
library among other things.

Update vendoring for Gitaly

See merge request !148

Handle internal API errors when getting merge request URLs

See merge request !145