Explicit vendored click_completion *.j2 entry in MANIFEST.in

[daogilvie]

This seems to be needed to make sure they are included in distributions.
Tiny change. Let me know if you want it done differently!

See #2422 for prior context.

Detecting the Problem

1. Build a bdist or sdist with setuptools and no cached egg-info.
2. Verify that no .j2 files are included in any of the stdout lines
3. Optionally unpack the dists and verify the click_completion vendor directory contains no .j2 files

Detecting the fix

After doing this, verify the following:

• The .j2 files appear as being copied in the output lines of the build log
• The .j2 files are in the vendored directory for click_completion

Due diligence

• Python 2.7 test suite passes
• Python 3 test suite passes

test_resolver_unique_markers failed (1 runs remaining out of 2).
	<class 'AssertionError'>
	assert 1 == 0
 +  where 1 = <Command 'pipenv install vcrpy==1.11.0'>.return_code
	[<TracebackEntry pipenv/tests/integration/test_install_markers.py:142>]
test_resolver_unique_markers failed; it passed 0 out of the required 1 times.
	<class 'AssertionError'>
	assert 1 == 0
 +  where 1 = <Command 'pipenv install vcrpy==1.11.0'>.return_code
	[<TracebackEntry pipenv/tests/integration/test_install_markers.py:142>]

I do not have time currently to investigate the reason the vcrpy spec string test fails, and cannot see an open issue for it. This was inherited before making the fix. Tests run on CPython 3.6.5, MacOS High sierra.

[techalchemy]

I am quite confident the test suites will pass :) thanks!

[techalchemy]

the VCRPY issue is an old one, you may just need to clear your cache to fix it locally

[techalchemy]

thanks again, merging!