Kill unused `MANIFEST.in`. (#2309) #2373

Job	Run time
Check GitHub Organization	1s
tox -e py312-pip23_3_2	27m 37s
tox -e format-check,lint-check,typecheck,vendor-check,package	4m 20s
tox -e py312-pip23_3_2-integration	41m 4s
./dtox.sh -e py27-pip20	11m 26s
./dtox.sh -e py35-pip20	13m 27s
./dtox.sh -e py311-pip20	15m 7s
./dtox.sh -e py311-pip22_3_1	16m 31s
./dtox.sh -e py311-pip23_1_2	16m 21s
./dtox.sh -e py312-pip23_3_2	15m 3s
./dtox.sh -e pypy310-pip20	25m 27s
./dtox.sh -e pypy310-pip22_3_1	26m 5s
./dtox.sh -e pypy310-pip23_1_2	24m 11s
./dtox.sh -e py27-pip20-integration	21m 8s
./dtox.sh -e py37-pip22_3_1-integration	42m 43s
./dtox.sh -e py37-pip23_1_2-integration	43m 16s
./dtox.sh -e py311-pip20-integration	25m 4s
./dtox.sh -e py311-pip22_3_1-integration	30m 11s
./dtox.sh -e py311-pip23_1_2-integration	28m 9s
./dtox.sh -e py312-pip23_3_2-integration	35m 56s
./dtox.sh -e pypy310-pip20-integration	45m 59s
./dtox.sh -e pypy310-pip22_3_1-integration	55m 0s
./dtox.sh -e pypy310-pip23_1_2-integration	53m 29s
Gather Final Status	1s
	10h 17m 36s

Provide feedback