remove platform directive as all plaforms are supported

As per recommendation from @wbond, removed platform directive of
["osx", "linux", "windows"] because that is the default when not
specified.

repository/s.json

@@ -567,7 +567,6 @@
 			"releases": [
 				{
 					"sublime_text": ">=3083",
-					"platforms": ["osx", "linux", "windows"],
 					"tags": true
 				}
 			]