Update CAR INSTALL.md

CAR INSTALL.md

@@ -40,8 +40,8 @@ Close the file and carefully dismount and eject the two drives. Remove the SD ca
 ### Boot, Configure, Update 
 The first thing to do on a Pi would be to use the `raspi-config` tool to expand the file system to use the entire card. It might be useful to change the `hostname` too. Next, do the usual update and upgrade:
 ```
-# apt-get update
-# apt-get upgrade
+# apt update
+# apt upgrade
 # rpi-update
 ``` 
 **Note:** If you are following this guide but are using a full-size Rapsberry Pi with the built-in DAC, then, at this time of writing (September 2018) it is a good idea to update the Pi's firmware using `rpi-update` because a [significant improvement](https://github.com/raspberrypi/firmware/commit/200c2f4dd54b2048b5dcb8661ea3f232beb7d81e) has been made to the [timing software](https://github.com/raspberrypi/firmware/issues/1026) of the built-in audio DAC's drivers. It should be incorporated in firmware from Raspbian 4.14.66-v7 onwards.