[Python-Dev] Version and Last-Modified headers are no longer required in PEPs.

[R. David Murray]

The Version and Last-Modified headers required by PEP1 used to be
maintained by the version control system, but this is not true now that
we've switched to git.  We are therefore deprecating these headers and
have removed them from PEP1.  The PEP generation script now considers
them to be optional.

--David