chore: Add pg_upgrade docker build instructions to README

Author: marcbachmann

Dockerfile.upgrade

@@ -1,4 +1,4 @@
-FROM livingdocs/postgres:14.0
+FROM livingdocs/postgres:14.1
 USER root
 RUN set -e \
   export DEBIAN_FRONTEND=noninteractive && \

README.md

@@ -37,6 +37,7 @@ docker build -t livingdocs/postgres:14.1 .
 
 # To build and push the multi-arch manifest to docker hub
 docker buildx build --platform linux/amd64,linux/arm64 -t livingdocs/postgres:14.1 --push .
+docker buildx build --platform linux/amd64,linux/arm64 -t livingdocs/postgres:14.1-upgrade --push  -f Dockerfile.upgrade .
 ```
 
 ## Set up streaming replication