Updating to ForgeGrade 5.1+

Hello,

I have been running into a small issue while updating to ForgeGradle 5.1+ . I have been using:compile fileTree("C:/AmpzLibz") in my dependencies section of my build.gradle like so:

to import various local jars that I use in making my mod. However, upon using this in gradle 5.1, I am greeted with the following error:

I imagine the keyword to add local files has changed, but I wouldn't know where to look for it. If anyone could let me know what it's changed to or where to look, I would really appreciate it.