Specify library dependencies in library.properties

Specifying the library dependencies in the depends field of library.properties causes the Arduino Library Manager (Arduino IDE 1.8.10 and newer) to offer to install any missing dependencies during installation of this library. "arduino-cli lib install" will automatically install the dependencies (arduino-cli 0.7.0 and newer).

library.properties

@@ -7,3 +7,4 @@ paragraph=Library for controlling Lixie II displays!
 category=Signal Input/Output
 url=https://github.com/connornishijima/Lixie_II
 architectures=*
+depends=FastLED