ci/ubuntu-rolling: remove pkg-config-arm-linux-gnueabihf

This has been removed as an explicit package in impish. It seems that
having pkg-config installed and adding arm as an arch will cause it to
be generated automatically

ci/ciimage/ubuntu-rolling/install.sh

@@ -12,7 +12,6 @@ pkgs=(
   python3-pip libxml2-dev libxslt1-dev libyaml-dev libjson-glib-dev
   wget unzip
   qt5-qmake qtbase5-dev qtchooser qtbase5-dev-tools clang
-  pkg-config-arm-linux-gnueabihf
   libomp-dev
   llvm lcov
   dub ldc