Balay/petsc 3.13.0 (#15767)

* petsc: add 3.13.0 (using petsc-lite) and 3.12.5

* petsc@3.13.0: update hdf5 and superlu-dist dependencies

* flake8 fix

* fixes for comments

Co-authored-by: Jed Brown <jed@jedbrown.org>