Bump dockerfiles to use ruby 3

* cloudfoundry/cloud_controller_ng#2619

Co-authored-by: Michael Oleske <moleske@pivotal.io>
Co-authored-by: Seth Boyles <sboyles@pivotal.io>

capi-migration-compatibility/Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:2.7-buster
+FROM ruby:3.0-buster
 
 ENV bosh_cli_version 6.4.17
 ENV bbl_version 7.2.12

capi-ruby-units/Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:2.7-buster
+FROM ruby:3.0-buster
 MAINTAINER https://github.com/cloudfoundry/capi-dockerfiles
 
 RUN set -ex \

capi-runtime-ci/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:trusty
+FROM ruby:3.0-buster
 
 ENV bosh_cli_version 6.4.17
 
@@ -8,60 +8,25 @@ RUN \
   echo "[ -f ~/.bashrc ] && source ~/.bashrc" >> $HOME/.bash_profile
 
 RUN \
-  echo "deb http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse" > /etc/apt/sources.list.d/backports.list && \
   apt-get update && \
   apt-get -y install \
-    bison \
     build-essential \
     curl \
     debconf-utils \
-    jq/trusty-backports \
+    git \
     libcurl4-openssl-dev \
-    libmysqlclient-dev \
     libpq-dev \
     libreadline-dev \
     libsqlite3-dev \
     libssl-dev \
     libxml2-dev \
     libxslt-dev \
     libyaml-dev \
-    mercurial \
-    python-software-properties \
     software-properties-common \
-    python-pip \
     unzip \
     wget \
     zip \
     zlib1g-dev
 
-RUN \
-  add-apt-repository ppa:git-core/ppa -y && \
-  apt-get update && \
-  apt-get install -y git && \
-  apt-get remove -y --purge software-properties-common
-
-RUN \
-  wget https://github.com/postmodern/ruby-install/archive/v0.4.1.tar.gz -P /tmp && \
-  tar zxf /tmp/v0.4.1.tar.gz -C /tmp && \
-  cd /tmp/ruby-install-0.4.1 && make install && \
-  ruby-install ruby 2.7.2 && \
-  rm -rf /usr/local/src/ruby-2.7.2 && \
-  rm -rf /tmp/*
-
-RUN \
-  git clone https://github.com/postmodern/chruby /tmp/chruby && \
-  cd /tmp/chruby && git reset --hard 310bd34d1fcbb3365814c85018114123cef5a41f && \
-  cd /tmp/chruby && ./scripts/setup.sh && \
-  echo 'source /usr/local/share/chruby/chruby.sh' >> $HOME/.bashrc && \
-  echo 'chruby 2.7.2' >> $HOME/.bashrc && \
-  rm -rf /tmp/*
-
-RUN \
-  bash -l -c "gem update --system" && \
-  bash -l -c "gem install bundler -v 2.1.4 --no-document --force"
-
-# Remove current default versions of bundler as we want to use 2.1.4
-RUN ls /opt/rubies/ruby-2.7.2/lib/ruby/gems/2.7.0/specifications/default/bundler-* | grep bundler-2.1.4 -v | xargs rm
-
 RUN wget -O /usr/local/bin/bosh https://s3.amazonaws.com/bosh-cli-artifacts/bosh-cli-${bosh_cli_version}-linux-amd64
 RUN chmod +x /usr/local/bin/bosh