update cc-znp serialport dep to latest version to get nodejs 12 support

The complete serialport 7.1.5 package list should be:

- @serialport/bindings@2.0.7
 - @serialport/list@1.1.4
 - @serialport/parser-inter-byte-timeout@1.1.0
 - @serialport/repl@1.1.4
 - serialport@7.1.4
 - @serialport/terminal@1.1.4