New issue by zeylos on void-packages repository

https://github.com/void-linux/void-packages/issues/15738

Description:
<!-- Don't request update of package. We have a script for that. https://alpha.de.repo.voidlinux.org/void-updates/void-updates.txt . However, a quality pull request may help. -->
Hi there,

First, thanks for the great work.
It seems we have an issue with the last firefox upgrade, it depends on some libs that aren't in the repos, here's the debug (produced with `xbps-install -Syud`) :
```
[DEBUG] firefox-69.0.3_2: requires dependency 'libevent>=2.1.11_1': installed `libevent-2.1.10_2', must be updated
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current' at index 0
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/multilib/nonfree' at index 1
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/multilib' at index 2
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/nonfree' at index 3
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current' at index 0
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/multilib/nonfree' at index 1
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/multilib' at index 2
[DEBUG] [rpool] checking `https://alpha.de.repo.voidlinux.org/current/nonfree' at index 3
[DEBUG] `libevent>=2.1.11_1' added into the missing deps array.
[DEBUG] firefox-69.0.3_2: requires dependency 'libvpx5>=1.7.0_1': installed `libvpx5-1.7.0_3'.
[DEBUG] firefox-69.0.3_2: requires dependency 'pixman>=0.14.0_1': installed `pixman-0.38.4_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'alsa-lib>=1.0.20_1': installed `alsa-lib-1.1.9_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'libsndio>=1.4.0_1': installed `libsndio-1.6.0_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'dbus-glib>=0.80_1': installed `dbus-glib-0.110_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'dbus-libs>=1.2.10_1': installed `dbus-libs-1.12.16_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'glib>=2.18.0_1': installed `glib-2.62.1_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'pango>=1.24.0_1': installed `pango-1.42.4_4'.
[DEBUG] firefox-69.0.3_2: requires dependency 'atk>=1.26.0_1': installed `atk-2.34.1_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'cairo>=1.8.6_1': installed `cairo-1.16.0_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'gdk-pixbuf>=2.22.0_1': installed `gdk-pixbuf-2.40.0_1'.
[DEBUG] firefox-69.0.3_2: requires dependency 'startup-notification>=0.10_1': installed `startup-notification-0.12_10'.
[DEBUG] firefox-69.0.3_2: requires dependency 'libXt>=1.0.5_1': installed `libXt-1.2.0_1'.
MISSING: libevent>=2.1.11_1
Transaction aborted due to unresolved dependencies.
[DEBUG] xbps_pkgdb_unlock: pkgdb_fd 8
[DEBUG] [pkgdb] released ok.
```
### System

* xuname:  
```
Void 5.2.20_1 x86_64 GenuineIntel uptodate rrrmFFFF
```
* package:  
`firefox-69.0.3_2`

### Expected behavior
Actually upgrade my packages ? ;)
### Actual behavior
MISSING: libevent>=2.1.11_1
Transaction aborted due to unresolved dependencies.

### Steps to reproduce the behavior
`xbps-install firefox` or `xbps-install -Syu` with firefox<=69.0.3_1 installed.

Thanks in advance for the fix,
King regards