The option isn't required to accept self-signed certs

On the other hand, if the option set to true it makes
machine-in-the-middle attack possible

Let's clarify it in the code that the option is deprecated

Suppress internal errors in client output

See merge request gitlab-org/gitlab-shell!549

Until recently, Gitaly was silently swallowing any errors returned by
SSH `git upload-pack` processes. Clients would still receive stderr
output and a non-zero return code, but Gitlab-Shell would receive error
as nil and log success.

With 9deaf47f1ecb00f0f36d18ee4a0fb1576f5a0efe Gitaly will now return an
error when git fails, but this causes Gitlab-Shell to print out the
GRPC error code as a message to the client:

> fatal: couldn't find remote ref not-a-real-ref
> fatal: the remote end hung up unexpectedly
> remote:
> remote:
> ========================================================================
> remote:
> remote: rpc error: code = Internal desc = SSHUploadPack: exit status 128
> remote:
> remote:
> ========================================================================
> remote:

The `remote:` text gives no additional context for the user and adds
clutter.

This commit suppresses the additional message added by Gitlab-Shell on
failure when the error type is `Internal`, returning client output to
the format it was prior to the Gitaly change.

Send full git request/response in SSHD tests

See merge request gitlab-org/gitlab-shell!550

Before 9deaf47f1ecb00f0f36d18ee4a0fb1576f5a0efe, Gitaly would return
success for `SSHUploadPack` and `SSHUploadArchive` regardless of the
exit code of the `git upload-pack|archive` process. As a result, the
gitlab-sshd acceptance tests could rely on no errors being returned from
Gitaly.

Currently these tests send the minimum request needed to start a
session, causing the server git process to fail as the `0000` flush
packet to end the session is never sent.

This commit fixes the tests by sending the full request/response needed
for a successful git operation.

Bump .tool_versions to use Go v1.16.12

See merge request gitlab-org/gitlab-shell!548

Part of https://gitlab.com/groups/gitlab-org/-/epics/7111

Release v13.22.1

See merge request gitlab-org/gitlab-shell!547

Remove SSL_CERT_DIR logging

See merge request gitlab-org/gitlab-shell!546

This log entry doesn't respect log level, because the log level
is configured after this logging happens

Fix usage of out-of-date Gitaly images

See merge request gitlab-org/gitlab-shell!544

Refactor flaky test case in sshd_test

See merge request gitlab-org/gitlab-shell!545

- Use require.Regexp to expect ssh handshake error
- Use require.Eventually to refactor verifyStatus

Our CI jobs and docker-compose pull in the "latest" tag of Gitaly. As it
turns out though, "latest" is pointing to Gitaly v13.3.0-rc5, which is
definitely not the latest versionat this point in time. This is because
CNG was converted to not use the "latest" tag anymore, but instead to
use a tag called "master" in gitlab-org/build/CNG!519.

Fix this by using the new "master" tag instead.

Update gitlab-shell VERSION to 13.22.0

See merge request gitlab-org/gitlab-shell!543

Release v13.22.0

See merge request gitlab-org/gitlab-shell!541

Fix golang definition in tool versions

See merge request gitlab-org/gitlab-shell!542

Relax key and username matching for sshd

See merge request gitlab-org/gitlab-shell!540

Due to the way sshd works, gitlab-shell could be called with a single
string in the form:

```
/path/to/gitlab-shell -c key-id
```

However, due to the tightening of the regular expressions in fcff692b
this string no longer matches, so logins would fail with:

```
Failed to get username: who='' is invalid
```

This can be reproduced by changing the user's shell to point to
gitlab-shell. For example:

```
usermod git -s /opt/gitlab/embedded/service/gitlab-shell/bin/gitlab-shell
```

While setting gitlab-shell as the user's shell isn't officially
supported, gitlab-shell still should be able to cope with the key being
specified as the last argument. We now split the argument list and use
the last value.

Relates to https://gitlab.com/gitlab-org/gitlab-shell/-/issues/530

Add logging to handler/exec.go and config/config.go

See merge request gitlab-org/gitlab-shell!539

Improve logging for non-git commands

See merge request gitlab-org/gitlab-shell!538

Reject non-proxied connections when proxy protocol is enabled

Closes #532

See merge request gitlab-org/gitlab-shell!536

Several of our commands only touch the internal API, and go nowhere
near Gitaly. Improve logging for each of these in a single MR. In
general, we want to be able to tell what happened in the execution of
each command, and to track failures down to a specific line of code.

Changelog: added

Update to Go v1.16.9

See merge request gitlab-org/gitlab-shell!537

This is a security release: https://golang.org/doc/devel/release#go1.16

refactor: remove call to BuildNameToCertificate (deprecated)

See merge request gitlab-org/gitlab-shell!515

This will help to prevent misconfigurations.

Changelog: fixed

Log command invocation

See merge request gitlab-org/gitlab-shell!535

Use reflection to log the command we are about to execute, both in
gitlab-shell and gitlab-sshd. Include the environment, which has all
the context we need to understand what the command is expected to do.

Changelog: added

Fix logging channel type

See merge request gitlab-org/gitlab-shell!534