docs: macOS installation guideline

Author: lukashornych

README.md

@@ -74,6 +74,19 @@ Binaries are available for all major platforms (Windows, Linux, macOS). You can
 _Note: evitaLab Desktop versioning is separate from the evitaLab core versioning. Just pick the newest desktop app version
 no matter your server version._
 
+### macOS
+
+Newer macOS versions quarantine not-signed apps (we are working on it), therefore after installation, macOS may
+throw error saying the app is broken. To prevent that, execute following command after installation to get the app out of 
+the quarantine:
+
+```shell
+cd /Applications
+sudo xattr -d com.apple.quarantine evitaLab.app
+```
+
+### Other platforms
+
 For other platforms, you will have to clone the repository and configure the [Electron Forge](https://www.electronforge.io/)
 config for you platform and build it with: