The first release of the Go buildpack after March 27, 2020 will no longer include Go versions 1.12.x. These Go versions will no longer be supported upstream. Please migrate your Go apps to supported versions of Go before that time.
Note: Unless you are manually specifying a version of Go for the buildpack to use, or you have customized your Go buildpack, no action is required.
As always, the buildpacks team is happy to answer questions you may have about this deprecation in the #buildpacks Slack channel.
Kashyap Vedurmudi, CF Buildpacks PM