Disabling Instructions

Close Google Chrome completely (press Cmd + Q).
Open the Terminal app (you can find it via Spotlight Cmd + Space or in the Applications -> Utilities folder).
Copy and paste the following command into the Terminal window:

bash
defaults write com.google.Chrome SuppressUnsupportedOSWarning -bool true 

Press Enter on your keyboard.
Relaunch Google Chrome.

The notification should disappear.

Note: If you want to restore the warning, enter the command
defaults delete com.google.Chrome in Terminal SuppressUnsupportedOSWarning.