Remove the documentation action

Since we already use the Swift Package Index to generate doc

.github/workflows/documentation.yaml

@@ -1,33 +0,0 @@
-name: Documentation
-
-on:
-  workflow_dispatch: {}
-  push:
-    branches:
-      - master
-    paths:
-      - .github/workflows/documentation.yaml
-      - Sources/**.swift
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Generate Documentation
-        uses: SwiftDocOrg/swift-doc@master
-        with:
-          inputs: "Sources"
-          output: "Documentation"
-          format: "html"
-          module-name: "Kingfisher"
-          base-url: "/"
-      - name: Upload Documentation Netlify
-        uses: netlify/actions/cli@master
-        with:
-          args: deploy --dir=Documentation --prod
-        env:
-          NETLIFY_SITE_ID: ${{ secrets.NETLIFY_SITE_ID }}
-          NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}