If I use the flag package like this:

branch := flag.String("branch", "master", "Branch to deploy")

and then invoke it at the command line like this:

go run main.go --branch=mybranch

It works just fine. By contrast, github-release complains that these are "invalid trailing arguments:"

Error: Invalid trailing arguments: [--branch=master]

It's confusing because it's not obvious what the mistake is, and the syntax is valid per the Golang flag package rules.