Allow installing experimental brightness ctl on fpp

plugininfo.json

{
	"repoName": "fpp-brightness",
	"name": "Brightness Control Plugin for FPP",
	"author": "Daniel Kulp (dkulp)",
	"description": "This plugin allows dynamic/real time control of the brightness of the display.",
	"homeURL": "https://github.com/challgren/fpp-brightness",
	"srcURL": "https://github.com/challgren/fpp-brightness.git",
	"bugURL": "https://github.com/challgren/fpp-brightness/issues",
	"allowUpdates": 1,
	"versions": [
		{
			"minFPPVersion": "3.3",
			"maxFPPVersion": "4.99",
			"branch": "master",
			"sha": "a27c0b6b91c87ee82c0384053867b725c80f7265"
		},
        {
            "minFPPVersion": "5.0",
            "maxFPPVersion": "5.99",
            "branch": "master",
            "sha": "64713ae0d47bfb419314e92747a78b6704d81aaa"
        },
        {
            "minFPPVersion": "6.0",
            "maxFPPVersion": "6.99",
            "branch": "master",
            "sha": "321ddb1efca1f01ede7bffb0e5ac94e9e4095c1b"
        },
        {
            "minFPPVersion": "7.0",
            "maxFPPVersion": "7.99",
            "branch": "master",
            "sha": ""
        },
	    {
            "minFPPVersion": "8.0",
            "maxFPPVersion": "0",
            "branch": "master",
            "sha": ""
        },
	    {
            "minFPPVersion": "9.0",
            "maxFPPVersion": "0",
            "branch": "master",
            "sha": ""
        }	
	]
}