Fix MANIFEST.in includes

[nickumia-reisys]

Related to

• Replace DCAT-US validator data.gov#3503
• Datajson Validator Documentation #123
• Datajson Validator Route #122

The templates directories were renamed and those were not included in MANIFEST.in

[github-actions]

✅ Result of Pytest Coverage

---------- coverage: platform linux, python 3.8.10-final-0 -----------

Name	Stmts	Miss	Cover
ckanext/datajson/init.py	6	6	0%
ckanext/datajson/blueprint.py	222	46	79%
ckanext/datajson/datajson.py	436	113	74%
ckanext/datajson/datajsonvalidator.py	71	71	0%
ckanext/datajson/exceptions.py	2	0	100%
ckanext/datajson/harvester_base.py	3	0	100%
ckanext/datajson/harvester_cmsdatanavigator.py	63	63	0%
ckanext/datajson/harvester_datajson.py	49	13	73%
ckanext/datajson/helpers.py	111	43	61%
ckanext/datajson/package2pod.py	302	164	46%
ckanext/datajson/parse_datajson.py	105	32	70%
ckanext/datajson/plugin.py	34	1	97%
TOTAL	1404	552	61%
Required	test	coverage	of
==================	34	passed,	3941