[Dwarf-discuss] ISSUE: update Dwarf_Version_Numbers.md for DWARF5

[Cary Coutant]

> It looks like https://wiki.dwarfstd.org/Dwarf_Version_Numbers.md hasn't
> been brought up to date with DWARF5 yet. This table can be useful
> because the versions of different sections do not necessarily follow the
> major DWARF version.

It hadn't even been updated to the final DWARF4 spec. I've updated it
with the latest from the DWARF5 spec. I didn't bother with the .dwo
sections, since they're basically the same (in v5) as their
corresponding non-dwo sections.

> While we are at it and preparing DWARF6 it would be a great hint to tool
> developers to know where they need to focus effort by keeping this table
> up to date with the evolving DWARF6.

I didn't add a column for DWARF6. I don't think we're close enough yet
to give any guidance there.

-cary