ci: Update gtk to 4.8.1

And follow release tags instead of branches.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1110>

ci/images_template.yml

@@ -1,4 +1,4 @@
 variables:
-  GST_RS_IMG_TAG: '2022-09-22.0'
+  GST_RS_IMG_TAG: '2022-09-23.0'
   GST_RS_STABLE: '1.64.0'
   GST_RS_MSRV: '1.63.0'

ci/install-gtk4.sh

@@ -1,10 +1,13 @@
+#! /bin/sh
+
 set -eux
 
-BRANCH=gtk-4-6
+BRANCH=4.8.1
 
 git clone https://gitlab.gnome.org/GNOME/gtk.git --branch $BRANCH --depth=1
 cd gtk
-meson build -D prefix=/usr/local -Dbuild-tests=false
+
+meson build -D prefix=/usr/local -Dbuild-tests=false -Dwayland-protocols:tests=false
 ninja -C build
 ninja -C build install
 cd ..

ci/windows-docker/install_gtk.ps1

@@ -1,7 +1,7 @@
 [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;
 
 # Download gstreamer and all its subprojects
-git clone -b gtk-4-6 --depth 1 https://gitlab.gnome.org/gnome/gtk.git C:\gtk
+git clone -b 4.8.1 --depth 1 https://gitlab.gnome.org/gnome/gtk.git C:\gtk
 if (!$?) {
   Write-Host "Failed to clone gtk"
   Exit 1