Add arm releases (rs#43)

Add support for OPTIONS method

Fixes rs#36

Fix help with last version of curl

Fixes rs#33

Fix travis condition

Upgrade Go version to 1.15

Fix goreleaser syntax

Fix goreleaser config

Update README.md

Use basic colors (rs#17)

Use basic ANSI colors to help readability with various terminal themes.

Do not duplicate Content-Type and Accept headers if provided

Fixes: rs#4