docs: Add note on node version when building (#333)

I heard several people had issues installing the project locally due to
not noticing the difference between node version required to run vs to
build the project. This improvement aims at helping in those cases and
hopefully preventing small waste of time.

Co-authored-by: Piotr Paulski <piotrpaulski@chromium.org>

Author: 2 people

CONTRIBUTING.md

@@ -39,6 +39,8 @@ for PR and commit titles.
 
 ## Installation
 
+Check that you are using node version specified in .nvmrc, then run following commands:
+
 ```sh
 git clone https://github.com/ChromeDevTools/chrome-devtools-mcp.git
 cd chrome-devtools-mcp