Update README.md

Update README.md to include installation of `python3-pip`.

README.md

@@ -47,14 +47,15 @@ If your display's resolution is not 1920x720, you will also need to change the c
 * libspatialindex-c6
 * yaml
 
-```
+```shell
 $ sudo apt install python3-iso8601 python3-zeep libsdl2-ttf-2.0-0 python3-numpy python3-pandas python3-fiona python3-pyproj libspatialindex-c6 python3-yaml
 ```
 
 * pygame 2
 * GTFS-Kit
 
-```
+```shell
+$ sudo apt install python3-pip
 $ sudo pip3 install pygame gtfs_kit
 ```