go get fails on Fedora 35

[CodingGhost]

doing go get github.com/apache/mynewt-mcumgr-cli/mcumgr fails on fedora35 with
helper_unsafe.go:146: undefined reference to `reflect.unsafe_New'

[utzig]

Check what's your system's go version? This tool requires at least Go 1.12.

[CodingGhost]

@utzig im on go 1.16.5