CI: DELETEME: Use my fork of gtk-rs compatible with enum funcs

Author: MarijnS95

.github/workflows/main.yaml

@@ -160,8 +160,8 @@ jobs:
       - name: "Acquire gtk-rs"
         uses: actions/checkout@v2
         with:
-          repository: gtk-rs/gtk-rs
-          ref: master
+          repository: MarijnS95/gtk-rs
+          ref: enum-functions
           path: gtk-rs
         if: matrix.os == 'ubuntu-20.04'
       - name: "Attempt to rebuild GTK gir"