Revert "libArcus: update to 4.8.0."

The cura/cura-engine/libArcus v4.8.0 toolchain requires some additional
dependencies that are not yet packaged, so go back to a working version
until everything is in order.

This reverts commit 843ef3e342.

srcpkgs/libArcus/template

@@ -1,7 +1,8 @@
 # Template file for 'libArcus'
 pkgname=libArcus
-version=4.8.0
-revision=1
+reverts=4.8.0_1
+version=4.7.1
+revision=4
 build_style=cmake
 configure_args="-DBUILD_EXAMPLES=OFF"
 hostmakedepends="protobuf python3-sip-devel"
@@ -12,7 +13,7 @@ maintainer="Karl Nilsson <karl.robert.nilsson@gmail.com>"
 license="LGPL-3.0-or-later"
 homepage="https://github.com/Ultimaker/libArcus"
 distfiles="https://github.com/Ultimaker/libArcus/archive/${version}.tar.gz"
-checksum=f5a7234506c89a36adccdab2a3c410a75aaaa9e7c7f9533db834881c59001677
+checksum=ba35ebecf4112ccfbe2b493c0e10e0276e85e0d449ce82cfa7590165b801facf
 
 libArcus-devel_package() {
 	depends="${sourcepkg}>=${version}_${revision}"