ci: Remove unneeded docker retention workflow

.github/workflows/docker-retention.yml

@@ -1,25 +0,0 @@
-# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
-name: Docker Retention
-
-on:
-  workflow_dispatch: # TEMP
-  schedule:
-    - cron: '0 0 * * *'
-
-jobs:
-  retention:
-    name: Enforce Retention Policy
-    runs-on: ubuntu-latest
-    steps:
-      - name: Delete old pre-release images
-        uses: snok/container-retention-policy@v2
-        with:
-          image-names: recyclarr
-          filter-tags: '*-dev.*'
-          cut-off: One week ago CST
-          keep-at-least: 1
-          account-type: org
-          org-name: recyclarr
-          token: ${{ secrets.GITHUB_TOKEN }}
-          token-type: github-token
-          dry-run: true # TEMP