doc: update meson version in README.md
Meson is now required to be at least 0.59 See https://gitlab.freedesktop.org/gstreamer/gstreamer/-/blob/main/meson.build#L3
This just updates the documentation to match.
Meson is now required to be at least 0.59 See https://gitlab.freedesktop.org/gstreamer/gstreamer/-/blob/main/meson.build#L3
This just updates the documentation to match.