We no longer need the workaround as the config file has been
renamed from `.erb` to `.tpl`.

Copies the `/etc/gitaly/config.toml.erb` file as
`/etc/gitaly/config.toml` file as the latest version of gitaly
CNG image no longer writes it but is required by Gitaly to run.

This job is added per the documentation:
https://docs.gitlab.com/ee/development/go_guide/#automatic-linting

Add libkrb5-dev to golangci-lint job

This is needed to process internal/sshd/gssapi.go.

Go v1.21 was just released today (https://go.dev/doc/go1.21), so let's
make sure our builds work with it.

All changes in our fork have been upstreamed in the latest `master` of
`golang.org/x/crypto`, so upgrade to that version. This version
requires Go 1.19 due to a new UNIX build constraint
(https://gitlab.com/gitlab-org/golang-crypto/-/merge_requests/13#note_1462100383).

Relates to https://gitlab.com/gitlab-org/gitlab-shell/-/issues/623

Changelog: changed

We want to use both go and ruby cache for test jobs since we run
go and rspec tests in that job.

We experienced a flaky failure of pipeline on `main` due to
caching changes.

To prevent that, we split the cache jobs specific to go and ruby
and use them accordingly. We also set the policy to `pull-push` on
specific jobs that need to update the cache.

We only use Ruby for running integration tests so we don't need
different versions of Ruby.

Signed-off-by: Balasankar "Balu" C <balasankar@gitlab.com>

This client bump includes plenty of improvement, espeically the support
for DNS service discovery in Gitaly/Praefect. This version requires Go
>= 1.18. As a result, we'll need to bump minimal Go version of GitLab
Shell accordingly.

What
---
Make the retryableHTTP client introduced in
https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/703 the
default HTTP client.

Why
---
In
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979#note_1254964426
we've seen a 99% error reduction on `git` commands from `gitlab-shell`
when the retryableHTTP client is used.

This has been running in production for over 2 weeks in `us-east1-b` and
5 days fleet-wide so we should be confident that this client works as
expected.

Reference: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979


Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>

What
---
- Update the `client.HttpClient` fields to have `http.Client` and
  `retryablehttp.Client`, one of them will be `nil` depending on the
  feature flag toggle.
- Create new method `newRetryableRequest` which will create a
  `retryablehttp.Request` and use that if the
  `FF_GITLAB_SHELL_RETRYABLE_HTTP` feature flag is turned on.
- Add checks for `FF_GITLAB_SHELL_RETRYABLE_HTTP` everywhere we use the
  http client to use the `retryablehttp.Client` or the default
  `http.Client`
- New job `tests-integration-retryableHttp` to run the integraiton tests
  with the new retryablehttp client. We didn't update go tests because
  some assertions are different and will break table driven tests.

Why
---
As discussed in
https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/703#note_1229645097
we want to put the client behind a feature flag, not just the retry
logic. This does bring extra risk for accessing a `nil` field but there
should be checks everytime we access `RetryableHTTP` and `HTTPClient`.

Reference: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979


Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>