Update README.md

Make commands easily executable within an IDE.

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

Author: tsegismont

vertx-pg-client/docker/postgres/README.md

@@ -8,12 +8,12 @@ Modify the content in the `docker compose.yml`
 
 ### Run the containers
 
-```
-> docker compose up --build -V
+```shell
+docker compose up --build -V
 ```
 
 ### Run tests
 
-```
-> mvn test -Dconnection.uri=postgres://postgres:postgres@localhost:5432/postgres -Dtls.connection.uri=postgres://postgres:postgres@localhost:5433/postgres -Dunix.socket.directory=/var/run/postgresql -Dunix.socket.port=5432
+```shell
+mvn test -Dconnection.uri=postgres://postgres:postgres@localhost:5432/postgres -Dtls.connection.uri=postgres://postgres:postgres@localhost:5433/postgres -Dunix.socket.directory=/var/run/postgresql -Dunix.socket.port=5432
 ```