gh actions: use repo-token in nim setup

.github/workflows/gen_bindings.yml

@@ -126,6 +126,7 @@ jobs:
       - uses: jiro4989/setup-nim-action@v1
         with:
          nim-version: 1.6.12
+         repo-token: ${{ secrets.GITHUB_TOKEN }}
       - uses: actions/checkout@v3
         with:
           repository: floooh/sokol-nim