virtual/pkgconfig: bump dev-util/pkgconf version.

virtual/pkgconfig: bump dev-util/pkgconf version.

Older versions of dev-util/pkgconf, notably 0.9.3, did not correctly
handle comments in .pc files, leading to errors like:

  Package # was not found in the pkg-config search path
  Package '#', required by '...', not found'

Bump the virtual's dependency on dev-util/pkgconf to a version that does
correctly support the comments, to ensure that all consuming packages
are upgraded.

Package-Manager: portage-2.3.6
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>