Allow folks to bring their own fly version

- As in some dev envs we might be dealing with multiple Concourses this
becomes handy.

Author: dlresende

ci/configure.sh

@@ -4,7 +4,9 @@ set -exu
 
 dir="$(dirname "$0")"
 
-fly -t "${CONCOURSE_TARGET:-production}" \
+FLY="${FLY_CLI:-fly}"
+
+"$FLY" -t "${CONCOURSE_TARGET:-production}" \
   sp -p os-conf-release \
   -c "$dir/pipeline.yml" \
   -l <(lpass show --notes 'os-conf-release pipeline vars') \