Rewrite ghcr.io in devcontainer features to use the pull through cache

Author: pantherman594

startupscript/butane/005-parse-devcontainer.sh

@@ -78,6 +78,11 @@ if [[ -d "${DEVCONTAINER_FEATURES_PATH}" ]]; then
     rsync -a --ignore-existing "${DEVCONTAINER_FEATURES_PATH}/" "${DEVCONTAINER_PATH}/.devcontainer/features"
 fi
 
+# Rewrite ghcr.io references to use the GAR pull-through cache
+readonly GHCR_CACHE="us-central1-docker.pkg.dev/workbench-app-cache/ghcr-cache"
+sed -i "s|ghcr\.io/|${GHCR_CACHE}/|g" "${DEVCONTAINER_CONFIG_PATH}"
+find "${DEVCONTAINER_PATH}/.devcontainer/features" -name devcontainer-feature.json -exec sed -i "s|ghcr\.io/|${GHCR_CACHE}/|g" {} +
+
 replace_template_options() {
     local TEMPLATE_PATH="$1"