[ci] remove singularity installation from pipeline

.CI-setup.sh

-#!/bin/bash
-
-### Setup singularity ###
-# adapted from: https://sylabs.io/guides/3.0/user-guide/installation.html
-# install dependencies
-apt-get update
-apt-get install -y \
-    build-essential \
-    libssl-dev \
-    uuid-dev \
-    libgpgme11-dev \
-    squashfs-tools \
-    libseccomp-dev \
-    pkg-config \
-    wget
-# yum update -y && \
-#     yum groupinstall -y 'Development Tools' && \
-#     yum install -y \
-#     openssl-devel \
-#     libuuid-devel \
-#     libseccomp-devel \
-#     wget \
-#     squashfs-tools
-
-
-
-# install go
-export GOVERSION=1.15.6 OS=linux ARCH=amd64
-wget https://dl.google.com/go/go$GOVERSION.$OS-$ARCH.tar.gz
-tar -C /usr/local -xzvf go$GOVERSION.$OS-$ARCH.tar.gz
-rm go$GOVERSION.$OS-$ARCH.tar.gz
-
-# install singularity
-export VERSION=3.9.1
-mkdir -p $GOPATH/src/github.com/sylabs
-cd $GOPATH/src/github.com/sylabs
-wget https://github.com/sylabs/singularity/releases/download/v${VERSION}/singularity-ce-${VERSION}.tar.gz
-tar -xzf singularity-ce-${VERSION}.tar.gz
-cd ./singularity
-./mconfig
-make -C ./builddir
-make -C ./builddir install
\ No newline at end of file