DeprecationWarning: the imp module is deprecated in favour of importlib

[stevepiercy]

Bug Report

Describe the bug
After generating a Pyramid project from the master branch of the pyramid-cookiecutter-starter and running tests, a DeprecationWarning is output:

DeprecationWarning: the imp module is deprecated in favour of importlib ; see the module's documentation for alternative uses import imp

To Reproduce
Run through the steps starting at https://docs.pylonsproject.org/projects/pyramid/en/master/narr/project.html#creating-the-project and end with running tests.

Expected behavior
No deprecation warning.

Additional context
These lines need to be updated:

pyramid/src/pyramid/path.py

Lines 4 to 15 in 323cfbb

	import imp
	from zope.interface import implementer
	from pyramid.interfaces import IAssetDescriptor
	ignore_types = [imp.C_EXTENSION, imp.C_BUILTIN]
	init_names = [
	'__init__%s' % x[0]
	for x in imp.get_suffixes()
	if x[0] and x[2] not in ignore_types
	]

I'm not sure how to fix this one. imp.get_suffixes() and imp.C_EXTENSION and imp.C_BUILTIN don't have clear replacements in importlib. I'm guessing it has something to do with importlib.machinery.all_suffixes(), importlib.machinery.EXTENSION_SUFFIXES, or importlib.machinery.SOURCE_SUFFIXES?