Allow nested namespaces in git URLs

Closes #74

See merge request !80

Proxy GET /info/refs to Gitaly

See merge request !105

Catch _all_ multipart NextPart() errors

Closes #89

See merge request !108

Replace 'gitlab_workhorse_artifacts_upload_*' with labeled version of 'gitlab_workhorse_multipart_upload_*'

Closes #88

See merge request !106

Set correct value of X-Forwarded-For header in PreAuthorize request

Closes #82

See merge request !104

Replace 'gitlab_workhorse_artifacts_upload_*' with labeled version of 'gitlab_workhorse_multipart_upload_*'

Version 1.2.1 changelog

See merge request !103

Add CI related requests metrics

This MR adds some metrics for CI related requests.

Related to gitlab-org/gitlab-ce/#23366, gitlab-com/infrastructure#583

See merge request !97

Prometheus metrics for multipart file extraction

See merge request !100

API improvements: buffering, metrics

Following discussion in https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/94

This closes a hole in our Unicorn response buffering. The responses should be small, hence buffering in-memory.

See merge request !102

Stop leaking error messages in 502 responses

Closes https://gitlab.com/gitlab-org/gitlab-workhorse/issues/72

See merge request !101

Add "make release" script

See merge request !99

Version 1.2.0

See merge request !98

Accelerate multipart file uploads for all requests

Companion to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5867

Extends the upload mechanism for CI artifacts to all multipart file uploads.

See merge request !58

Handle environments/:id/terminal.ws, providing access to terminal websockets

A GitLab environment may expose a terminal connection for out-of-band access. Workhorse is responsible for providing a websocket connection to the terminal if present. 

It authenticates the user and retrieves connection details from GitLab using the environments/:id/terminal.ws/authorize endpoint, and sets up a proxy to the terminal provider, converting from the remote's subprotocol to a common format.

Authentication is periodically re-done, and the connection will be broken if it fails, or if the connection details change in any way.

This MR includes support for the `channel.k8s.io` websocket subprotocol, allowing connections to be made to Kubernetes / OpenShift containers. 

Based on top of (some of) !72 

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/22864

See merge request !83

A GitLab environment may expose a terminal connection for out-of-band access.
Workhorse is responsible for providing a websocket connection to the terminal
if present.

It authenticates the user and retrieves connection details from GitLab using
the environments/:id/terminal.ws/authorize endpoint, and sets up a proxy to
the terminal provider, converting from the remote's subprotocol to a common
format.

Authentication is periodically re-done, and the connection will be broken if
it fails, or if the connection details change in any way.

Version 1.1.1

See merge request !96