Adopt new Arch Linux naming scheme for their official Docker images

arch-self-contained/Dockerfile

-FROM archlinux/base:latest
+FROM archlinux:base
 
 RUN pacman -Syu --noconfirm git cmake make grep awk patch gcc pkgconf automake autoconf mesa xorg-xrandr libxinerama libxcursor qt5-base nasm

arch-system-dependencies/Dockerfile

-FROM archlinux/base:latest
+FROM archlinux:base
 
 RUN pacman -Syu --noconfirm git cmake make grep awk patch gcc qt5-base mesa libjpeg-turbo libtiff bzip2 glfw cairo ffmpeg

deploy-to-aur/Dockerfile

-FROM archlinux:latest
+FROM archlinux:base-devel
 LABEL maintainer="Ingo Meyer <i.meyer@fz-juelich.de>"
 
-RUN pacman -Sy --noconfirm --needed base-devel git openssh && \
+RUN pacman -Sy --noconfirm --needed git openssh && \
     yes | pacman -Scc
 
 RUN useradd -m deploy