End support for MacOS X 10.10 (Yosemite) and FreeBSD prior to 11.2

Go 1.13 has ended runtime support for MacOS X 10.10 and prior (Yosemite and earlier) and for FreeBSD prior to 11.2. Once we switch to building Terraform with Go 1.13 we will therefore also end support for those operating systems.

This issue is here just as a placeholder to mark the impending breaking change such that we can plan to include it in a particular future release.

The issue is a placeholder about Terraform's future switch to Go 1.13 and its impact on macOS X 10.10 and FreeBSD before 11.2; no files, tests, or entry points are named. Start by reviewing the Go 1.13 support change and the planned release context. Done means the affected future release clearly ends support for those operating systems.

Written by the indexing model from the issue text.