🩹 fix README to prevent 'ERROR: failed to solve: invalid reference format: repository name must be lowercase'

and 'docker: invalid reference format: repository name must be lowercase.'

README.md

@@ -95,7 +95,7 @@ make install clean
 #### Using [containers](https://www.docker.com/)
 
 ```console
-docker build -t Y2Z/monolith .
+docker build -t y2z/monolith .
 sudo install -b dist/run-in-container.sh /usr/local/bin/monolith
 ```
 

dist/run-in-container.sh

@@ -7,4 +7,4 @@ if which podman 2>&1 > /dev/null; then
     DOCKER=podman
 fi
 
-$DOCKER run --rm Y2Z/$PROG_NAME "$@"
+$DOCKER run --rm y2z/$PROG_NAME "$@"