.github/workflows/flake-updates-input.yml: remove

this is broken on current (21.9) nix, isn't worth pinning an older version for the amount of use this gets

.github/workflows/flake-updates-input.yml

@@ -1,29 +0,0 @@
-name: "Update flakes - input"
-on:
-  repository_dispatch:
-  workflow_dispatch:
-    inputs:
-      flakeInput:
-        description: "flake input to update"
-        required: true
-        type: string
-jobs:
-  createPullRequest:
-    runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/master' # ensure workflow_dispatch only runs on master
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install Nix
-        uses: cachix/install-nix-action@v24
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-      - name: Update flake.lock
-        id: update
-        uses: DeterminateSystems/update-flake-lock@v20
-        with:
-          inputs: ${{ inputs.flakeInput }}
-      #- name: Enable Automerge
-      #  run: gh pr merge --rebase --auto "${{ steps.update.outputs.pull-request-number }}"
-      #  env:
-      #    GH_TOKEN: ${{ secrets.GH_TOKEN_FOR_UPDATES }}