pantsbuild.pants wheel does not work with Python 3.7

[Eric-Arellano]

Problem

Due to #7401 building the cryptography wheel as cp36-cp36m, rather than using the cp34-abi3 wheel from PyPi, Pants does not work properly with a Python 3.7 interpreter.

Specifically, it appears to fail if the user uses any contrib packages from PyPi. To reproduce, use this pants.ini and the ./pants script from the setup repo.

[GLOBAL]
pants_version: 1.15.0.dev4
pants_runtime_python_version: 3.7
plugins: [
    'pantsbuild.pants.contrib.go==%(pants_version)s',
  ]

Then running ./pants, you'll get the error:

Exception message: Could not satisfy all requirements for pantsbuild.pants==1.15.0rc0:
    pantsbuild.pants==1.15.0rc0(from: pantsbuild.pants.contrib.go==1.15.0rc0)

Solution coming soon

This can be fixed once pex-tool/pex#692 gets merged into Pants, as we'll be able to remove:

pants/build-support/bin/release.sh

Lines 213 to 220 in e620a9e

	# TODO(pex#539): This code hacks around Pex's issue in resolving abi3 values with an abi
	# from an earlier Python 3 version. Specifically, the cryptography wheel is normally marked as cp34-abi3,
	# meaning it supports any Python >= 3.4. But when running `release.sh -3p`, Pex will fail to
	# resolve the cryptography wheel we have. So, we work around this by building our own cryptography
	# wheel with `cp36-cp36m`.
	if [[ "${python_three:-false}" == "true" ]]; then
	wheel_args=("--no-binary=cryptography" "${wheel_args[@]}")
	fi