Implement support for `--exclude <req>`. #2290

Job	Run time
Check GitHub Organization	1s
tox -e py312-pip23_3_1	3h 54m 52s
tox -e py312-pip23_3_1-integration	1h 4m 57s
./dtox.sh -e py27-pip20	17m 45s
./dtox.sh -e py35-pip20	14m 11s
./dtox.sh -e py311-pip20	14m 36s
tox -e format-check,typecheck,vendor-check,package	4m 16s
./dtox.sh -e py311-pip22_3_1	23m 32s
./dtox.sh -e py311-pip23_1_2	16m 5s
./dtox.sh -e py312-pip23_3_1	18m 44s
./dtox.sh -e pypy310-pip20	28m 0s
./dtox.sh -e pypy310-pip22_3_1	27m 45s
./dtox.sh -e pypy310-pip23_1_2	28m 4s
./dtox.sh -e py27-pip20-integration	19m 27s
./dtox.sh -e py37-pip22_3_1-integration	1h 28m 20s
./dtox.sh -e py37-pip23_1_2-integration	1h 29m 20s
./dtox.sh -e py311-pip20-integration	21m 14s
./dtox.sh -e py311-pip22_3_1-integration	40m 10s
./dtox.sh -e py311-pip23_1_2-integration	27m 27s
./dtox.sh -e py312-pip23_3_1-integration	51m 16s
./dtox.sh -e pypy310-pip20-integration	1h 12m 26s
./dtox.sh -e pypy310-pip22_3_1-integration	52m 12s
./dtox.sh -e pypy310-pip23_1_2-integration	50m 24s
Gather Final Status	1s
	16h 45m 5s

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