README: rsync is used to get v8 sources

Author: krichprollsch

README.md

@@ -36,7 +36,7 @@ Fast web automation for AI agents, LLM training, scraping and testing:
 _Puppeteer requesting 100 pages from a local website on a AWS EC2 m5.large instance.
 See [benchmark details](https://github.com/lightpanda-io/demo)._
 
-[^1]: **Playwright support disclaimer:**  
+[^1]: **Playwright support disclaimer:**
 Due to the nature of Playwright, a script that works with the current version of the browser may not function correctly with a future version. Playwright uses an intermediate JavaScript layer that selects an execution strategy based on the browser's available features. If Lightpanda adds a new [Web API](https://developer.mozilla.org/en-US/docs/Web/API), Playwright may choose to execute different code for the same script. This new code path could attempt to use features that are not yet implemented. Lightpanda makes an effort to add compatibility tests, but we can't cover all scenarios. If you encounter an issue, please create a [GitHub issue](https://github.com/lightpanda-io/browser/issues) and include the last known working version of the script.
 
 ## Quick start
@@ -164,7 +164,7 @@ For Debian/Ubuntu based Linux:
 sudo apt install xz-utils \
     python3 ca-certificates git \
     pkg-config libglib2.0-dev \
-    gperf libexpat1-dev unzip \
+    gperf libexpat1-dev unzip rsync \
     cmake clang
 ```