v0.4.0

Changelog

d272890 Create go.yml
267470b README: update with mdsh
3be7626 Release v0.4.0
83a9cc5 Use branch as deployment ref by default (#1)
d4a5c3c add missing CHANGELOG.md
3b4d7ad bye Travis-CI
55f9cac convert to go modules
239bacc fix CLI parsing
68954f7 fix: handle pull-request URLs
5111335 forward API failures to the client
053eecd gitsrc: wrap errors for better reporting
3829824 please: trim the environmentURL
ccd4e44 release with goreleaser
2470bc3 restore the original environment name logic
a52bc24 update dependencies