Since upstream refuses to fix this issue:
https://github.com/elixir-lang/elixir/issues/12000
On rare occasions, our pre-release version, which is the prefix
of the git hash, might consist only of digits. Even more rarely, it
might start with a `0`. When that happens, Elixir will refuse to
parse that as a valid pre-release version (it wants it to be an
integer without a leading 0).
To prevent that, we will always prepend a "g" to the pre-release
version, ensuring it's never a valid number.