run-mypy: Check PROVISION_VERSION.
run-mypy: Check PROVISION_VERSION.

Since new mypy versions frequently break old versions, this check is a
useful way to help prevent problems where mypy output is wrong.

We could probably tighten this by checking explicitly the expected
mypy version from requirements.txt, but that's work.

Replaces #5026.

synicalsyntax/zulip,vaidap/zulip,showell/zulip,brainwane/zulip,brainwane/zulip,mahim97/zulip,kou/zulip,eeshangarg/zulip,verma-varsha/zulip,brockwhittaker/zulip,shubhamdhama/zulip,amanharitsh123/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,shubhamdhama/zulip,showell/zulip,dhcrzf/zulip,eeshangarg/zulip,verma-varsha/zulip,tommyip/zulip,amanharitsh123/zulip,timabbott/zulip,rishig/zulip,shubhamdhama/zulip,vaidap/zulip,rishig/zulip,dhcrzf/zulip,synicalsyntax/zulip,rht/zulip,vaidap/zulip,eeshangarg/zulip,brainwane/zulip,tommyip/zulip,jackrzhang/zulip,rishig/zulip,andersk/zulip,andersk/zulip,vaidap/zulip,rishig/zulip,tommyip/zulip,zulip/zulip,shubhamdhama/zulip,verma-varsha/zulip,amanharitsh123/zulip,punchagan/zulip,Galexrt/zulip,kou/zulip,kou/zulip,rht/zulip,andersk/zulip,punchagan/zulip,tommyip/zulip,dhcrzf/zulip,zulip/zulip,timabbott/zulip,timabbott/zulip,brockwhittaker/zulip,synicalsyntax/zulip,brockwhittaker/zulip,rishig/zulip,jackrzhang/zulip,zulip/zulip,hackerkid/zulip,zulip/zulip,jackrzhang/zulip,mahim97/zulip,kou/zulip,tommyip/zulip,shubhamdhama/zulip,shubhamdhama/zulip,andersk/zulip,synicalsyntax/zulip,showell/zulip,andersk/zulip,amanharitsh123/zulip,timabbott/zulip,shubhamdhama/zulip,vaidap/zulip,hackerkid/zulip,rht/zulip,rht/zulip,hackerkid/zulip,punchagan/zulip,dhcrzf/zulip,jackrzhang/zulip,Galexrt/zulip,rishig/zulip,amanharitsh123/zulip,tommyip/zulip,verma-varsha/zulip,dhcrzf/zulip,brainwane/zulip,hackerkid/zulip,eeshangarg/zulip,rht/zulip,rht/zulip,hackerkid/zulip,brainwane/zulip,timabbott/zulip,rishig/zulip,timabbott/zulip,Galexrt/zulip,Galexrt/zulip,synicalsyntax/zulip,andersk/zulip,zulip/zulip,tommyip/zulip,andersk/zulip,Galexrt/zulip,dhcrzf/zulip,mahim97/zulip,Galexrt/zulip,punchagan/zulip,showell/zulip,mahim97/zulip,punchagan/zulip,dhcrzf/zulip,rht/zulip,vaidap/zulip,showell/zulip,timabbott/zulip,jackrzhang/zulip,brockwhittaker/zulip,jackrzhang/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,hackerkid/zulip,jackrzhang/zulip,brainwane/zulip,synicalsyntax/zulip,showell/zulip,verma-varsha/zulip,zulip/zulip,eeshangarg/zulip,amanharitsh123/zulip,synicalsyntax/zulip,Galexrt/zulip,showell/zulip,mahim97/zulip,kou/zulip,zulip/zulip,brockwhittaker/zulip,brockwhittaker/zulip,verma-varsha/zulip,mahim97/zulip,brainwane/zulip,punchagan/zulip