Previously the -upgrade option was covered only on the "terraform init" usage page. It seems also worth mentioning in the main docs on provider versioning, since we're already explaining here other mechanics of the versioning/constraints system.
This escapes all characters that might have a special interpretation when embedded into a portion of a URL, including slashes, equals signs and ampersands.
Since Terraform's internals are not 8-bit clean (it assumes UTF-8
strings), we can't implement raw gzip directly. We're going to add
support where it makes sense for passing data to attributes as
base64 so that the result of this function can be used.
Chris Doherty