chore(cloudrun): migrate region tag "cloudrun_imageproc_dockerfile_imagemagick" (#4031)

Author: hivanalejandro

run/image-processing/Dockerfile

@@ -15,6 +15,7 @@
 # Use the official lightweight Node.js image.
 # https://hub.docker.com/_/node
 FROM node:20-slim
+# [START cloudrun_imageproc_dockerfile_nodejs]
 # [START cloudrun_imageproc_dockerfile_imagemagick]
 
 # Install Imagemagick into the container image.
@@ -26,6 +27,7 @@ RUN set -ex; \
   rm -rf /var/lib/apt/lists/*
 
 # [END cloudrun_imageproc_dockerfile_imagemagick]
+# [END cloudrun_imageproc_dockerfile_nodejs]
 
 # Create and change to the app directory.
 WORKDIR /usr/src/app