Fix $(pwd) invocation in readme example (#9519)

Now it matches the pglite example, and works.

README.md

@@ -67,7 +67,7 @@ docker run -d --name noco
 ## Docker with PG
 ```bash
 docker run -d --name noco 
-           -v "${pwd}"/nocodb:/usr/app/data/ 
+           -v "$(pwd)"/nocodb:/usr/app/data/ 
            -p 8080:8080 
             # replace with your pg connection string
            -e NC_DB="pg://host.docker.internal:5432?u=root&p=password&d=d1" 
@@ -179,4 +179,4 @@ Thank you for your contributions! We appreciate all the contributions from the c
 
 <a href="https://github.com/nocodb/nocodb/graphs/contributors">
   <img src="https://contrib.rocks/image?repo=nocodb/nocodb" />
-</a>
+</a>