Release v2.1.0

Closes #133

See merge request !168

Remove chatty ErrorPage log message

Closes #132

See merge request !167

This message is not very useful and it looks alarming because it
contains the word 'error'.

Filter query-string secrets out of logged URLs

See merge request !165

Suggest better default value for the prometheus port

Closes #87 and #86

See merge request !154

Reserved port[1] is now suggested

Fixes #86

[1]: https://github.com/prometheus/prometheus/wiki/Default-port-allocations

Support GL_REPOSITORY from API and pass it to Gitaly on ReceivePack

See merge request !162

Prometheus metrics for senddata and git archive cache

See merge request !163

Add internal upload to external storage

See merge request !148

Changelog for 2.0.0

See merge request !161

Gitaly stream interruption tests

Closes #128

See merge request !160

The socket path is / can be deterministic, leading to repeated
failures to open the listener when an old socket was never removed.

Use io.Copy in gitaly smarthttp

See merge request !159

Always cancel gRPC stream contexts

See merge request !158

Don't append error messages to Git response body

Closes #127

See merge request !157

Stop Fail500 and LogError from panicing with nil request or error

Closes #99

See merge request !156