build(archlinux): generate srcinfo file during build (#2826)

docker/archlinux.dockerfile

@@ -3,7 +3,7 @@
 # platforms: linux/amd64
 # archlinux does not have an arm64 base image
 # no-cache-filters: artifacts,sunshine
-ARG BASE=archlinux
+ARG BASE=archlinux/archlinux
 ARG TAG=base-devel
 FROM ${BASE}:${TAG} AS sunshine-base
 
@@ -13,6 +13,7 @@ RUN <<_DEPS
 set -e
 pacman -Syu --disable-download-timeout --needed --noconfirm \
   archlinux-keyring
+pacman -Scc --noconfirm
 _DEPS
 
 # Setup builder user, arch prevents running makepkg as root
@@ -45,6 +46,7 @@ pacman -Syu --disable-download-timeout --needed --noconfirm \
   git \
   namcap \
   xorg-server-xvfb
+pacman -Scc --noconfirm
 _DEPS
 
 # Setup builder user
@@ -80,6 +82,7 @@ _MAKE
 WORKDIR /build/sunshine/pkg
 RUN mv /build/sunshine/build/PKGBUILD .
 RUN mv /build/sunshine/build/sunshine.install .
+RUN makepkg --printsrcinfo > .SRCINFO
 
 # create a PKGBUILD archive
 USER root
@@ -121,6 +124,7 @@ pacman -Syu --disable-download-timeout --needed --noconfirm \
   archlinux-keyring
 pacman -U --disable-download-timeout --needed --noconfirm \
   /sunshine.pkg.tar.zst
+pacman -Scc --noconfirm
 _INSTALL_SUNSHINE
 
 # network setup

docs/source/about/setup.rst

@@ -97,12 +97,12 @@ Install
 
       .. tab:: Prebuilt Package
 
-         #. Open terminal and run the following code.
+         #. Follow the instructions at LizardByte's `pacman-repo <https://github.com/LizardByte/pacman-repo>`__ to add
+            the repository. Then run the following code.
 
             .. code-block:: bash
 
-               wget https://github.com/LizardByte/Sunshine/releases/latest/download/sunshine.pkg.tar.zst
-               pacman -U --noconfirm sunshine.pkg.tar.zst
+               pacman -S sunshine
 
          Uninstall:
             .. code-block:: bash