I recently migrated from Linux to macOS and with
go1.16.2 installed I noticed the following difference from my previous setup:
go1.15.3 the command
go get -u -v github.com/gohugoio/hugo compiled the latest unreleased Hugo DEV version when executed from within the Go default packages directory.
go1.16.2 the same command under the same folder compiled the latest Hugo release and not the DEV version.
After a bit of tinkering, I found out that executing the command from within my local Hugo fork that resides outside the Go packages directory compiles the DEV version.
P.S. Thanks @bep for clearing this up.