pidgin/pidgin

Fix Meson deprecation from Facebook docs

23 months ago, Elliott Sales de Andrade
ff4332b17f80
Fix Meson deprecation from Facebook docs

Fixes this deprecation:
```
../doc/reference/protocols/facebook/meson.build:25: WARNING: Project targeting '>=0.58.0' but tried to use feature deprecated since '0.56.0': meson.build_root. use meson.project_build_root() or meson.global_build_root() instead.
```

Testing Done:
Reconfigured and saw no warning.

Reviewed at https://reviews.imfreedom.org/r/1555/
---
id: im.pidgin.Pidgin3
runtime: org.gnome.Platform
runtime-version: '3.36'
sdk: org.gnome.Sdk
command: pidgin3
finish-args:
- --share=ipc
- --socket=fallback-x11
- --share=network
- --socket=pulseaudio
- --talk-name=org.freedesktop.Notifications
- --system-talk-name=org.freedesktop.Avahi
modules:
- packaging/flatpak/libpurple-common.yml
- packaging/flatpak/talkatu.yml
- name: pidgin3
buildsystem: meson
config-opts:
- -Dconsoleui=false
- -Ddoc=false
sources:
- type: dir
path: '.'