ucommon 6.2.2 (new formula)

It’s a useful secure library that does stuff; It has a pretty
complicated history, I’d drown the entire commit message if I tried to
explain what it does and why.

Closes #34437.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
ucommon: add 6.2.2 bottle.
docs: Python for formula authors

Closes #34228.
add ChinaDNS-C 1.1.8
add prefix to chinadns.
add test for chinadns.
make install only.
chinadns: add 1.1.8 bottle.