feat(build): Bump from Golang 1.12.12 to 1.12.16
This MR bumps the next release from Golang 1.12.12 to 1.12.16.
This just contains some small bugfixes and security fixes:
https://golang.org/doc/devel/release.html#go1.12.minor
This shouldn't have any effect or performance or features or otherwise.