Update tools/get-images.sh to capture images properly (#193)

* Update tools/get-images.sh to capture images properly

* Update tools/get-images.sh to match the logic found in other charm repos

* Update tools/get-images.sh to work in both Go and Python versions of yq

* Add set -xe to get-images.sh

tools/get-images.sh

@@ -3,7 +3,10 @@
 # This script returns list of container images that are managed by this charm and/or its workload
 #
 # dynamic list
+
+set -xe
+
 IMAGE_LIST=()
-IMAGE_LIST+=($(find -type f -name metadata.yaml -exec yq '.resources | to_entries | .[] | .value | ."upstream-source"' {} \;))
+IMAGE_LIST+=($(find -type f -name config.yaml -exec yq '.options | with_entries(select(.key | test("-image$"))) | .[].default' {} \; | tr -d '"'))
 printf "%s\n" "${IMAGE_LIST[@]}"