python 3.8 upgrade failures

[iMichka]

From #54912:

2020-07-07T09:29:34.0068870Z Error: 15 failed steps!
2020-07-07T09:29:34.0073170Z brew test --verbose adios2
2020-07-07T09:29:34.0074130Z brew test --verbose agda
2020-07-07T09:29:34.0074930Z brew test --verbose alure
2020-07-07T09:29:34.0075450Z brew test --verbose dps8m
2020-07-07T09:29:34.0075990Z brew fetch --retry ensmallen
2020-07-07T09:29:34.0076470Z brew fetch --retry evince
2020-07-07T09:29:34.0077030Z brew test --verbose howdoi
2020-07-07T09:29:34.0077530Z brew fetch --retry lc0
2020-07-07T09:29:34.0078030Z brew test --verbose ncview
2020-07-07T09:29:34.0078530Z brew test --verbose opentsdb
2020-07-07T09:29:34.0079010Z brew fetch --retry sile
2020-07-07T09:29:34.0079490Z brew linkage --test vcpkg
2020-07-07T09:29:34.0079970Z brew test --verbose vcpkg
2020-07-07T09:29:34.0080440Z brew test --verbose yafc
2020-07-07T09:29:34.0080950Z brew install --verbose --build-bottle bzt

These can be fixed once #54912 has been merged.

[fxcoudert]

All those actually seem fixed in the 3.9 migration PR, and I'll be opening a new tracking issue when I merge… so closing this one