Probably you have solved by this time, but i will do an explanation to myself from some hours ago with my bad english in case someone could need it.
-Go to the SDK of the rage plugin hook and copy the dll in the dependencies of your visual studio project
-Now if you have written in your code """"Game.WasKeyJustPressed(Keys.G)""" you will see it underlined in red because it was updated (I saw it in https://ragepluginhook.net/Downloads.aspx?Hook=1 the version 2.76 ) to """Input.WasKeyJustPressed(Keys.G)""",now when you compiled and used in rdr2 you shouldn't have that problem