ci: Update Github behavior.

.github/dependabot.yml

@@ -1,10 +1,5 @@
 version: 2
 updates:
-  - package-ecosystem: composer
-    directory: "/"
-    schedule:
-      interval: daily
-    open-pull-requests-limit: 10
   - package-ecosystem: github-actions
     directory: "/"
     schedule:

.github/workflows/upgrade-flakes.yaml

@@ -0,0 +1,58 @@
+name: 'Update flakes'
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '51 2 * * 0'
+
+jobs:
+  createPullRequest:
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Set git to use LF
+        run: |
+            git config --global core.autocrlf false
+            git config --global core.eol lf
+
+      - name: Checkout
+        uses: actions/[email protected]
+        with:
+            fetch-depth: 1
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v16
+        with:
+          install_url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
+          # Configure Nix to enable flakes
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+
+      - name: Run the general flake checks
+        run: nix flake check
+
+      - name: Make changes to pull request
+        run: nix flake update
+
+      - name: Create Pull Request
+        id: cpr
+        uses: peter-evans/create-pull-request@v3
+        with:
+          commit-message: 'flake: Update dependencies'
+          committer: 'GitHub <[email protected]>'
+          author: '${{ github.actor }} <${{ github.actor }}@users.noreply.github.com>'
+          signoff: false
+          branch: flake-updates
+          delete-branch: true
+          title: 'Upgrade flakes'
+          body: |
+            Update report
+            - Updated with *today's* date
+            - Auto-generated by [create-pull-request][1]
+
+            [1]: https://github.com/peter-evans/create-pull-request
+
+      - name: Check outputs
+        run: |
+          echo 'Pull Request Number - ${{ steps.cpr.outputs.pull-request-number }}'
+          echo 'Pull Request URL - ${{ steps.cpr.outputs.pull-request-url }}'