meson: rely on automatic wrap promotion from subprojects

Don't ship wrap files for things that are only dependencies
of dependencies, such as gperf (for fontconfig), or
libffi + proxy-libintl (for glib).

Instead, let Meson use the wraps that these subprojects ship,
which Meson will pick up automatically since v56, so there's
no need for us to ship these wraps any more.

Bump the Meson requirement to 0.56 accordingly.

Bump the Fedora image version used for the CI to F34
and bump the tag in order to use the latest version of things.

See https://mesonbuild.com/Release-notes-for-0-56-0.html#wraps-from-subprojects-are-automatically-promoted

Closes #445
7 jobs for meson-rely-on-subproject-wrap-promotion-for-indirectly-needed-wraps in 30 minutes and 11 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Prep
passed #7577196
fedora image

00:02:30

 
  Test
passed #7577197
fedora autotools build

00:27:40

passed #7577198
fedora meson build

00:00:50

passed #7577201
meson android arm64 fedora

00:02:11

passed #7577202
gst-macos-11.1
meson macOS

00:03:14

passed #7577199
docker windows 1809
meson vs2017 amd64

00:03:12

passed #7577200
docker windows 1809
meson vs2017 x86

00:03:16