textproc/go-md2man: update to 2.0.3

Rendering bug fixes:
- e5bd727 - Escape hyphens in links to avoid word wrap (@r10r)
- 66e0792 - Do not render links twice (@r10r)
- 65a740a - Do not typeset table headings in monospaced font (@kolyshkin)
- 43fb747 - Use .EX/.EE for code examples (@kolyshkin)
- d85280d - Silence warnings caused by \fC which is non-portable. (@debarshiray)

CLI improvements:
- e2293e7 - Don't warn on top-level comments (@mtrmac)

Other changes include code formatting and doc imporvements.
Thanks to all who helped make this release happen.

Adopt MAINTAINER.

(pin)