Update to 2.000008

Upstream changes:
2.000008 - 2019-08-05
  - reverting all changes from 2.000007 due to failures on some perl versions
    and a number of downstream users.  The changes will be reintroduced in a
    fixed form in a future version.

2.000007 - 2019-07-31
  - fix composing roles into packages that have stub subs in them
  - exclude all constant subs from method list

(wen)