ci: use forgejo workflows

.forgejo/workflows/test.yml

@@ -33,8 +33,8 @@ jobs:
       - name: Setup Attic Cache
         uses: ./
         with:
-          endpoint: ${{ secrets.ATTIC_ENDPOINT }}
-          cache: ${{ secrets.ATTIC_CACHE }}
+          endpoint: ${{ vars.ATTIC_ENDPOINT }}
+          cache: ${{ vars.ATTIC_CACHE }}
           token: ${{ secrets.ATTIC_TOKEN }}
 
       - name: Build Nix Package

.github/dependabot.yml

@@ -1,7 +0,0 @@
-version: 2
-
-updates:
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "weekly"