Support use-flutter option in groundskeeper workflow

.github/workflows/groundskeeper.yml

diff --git a/.github/workflows/groundskeeper.yml b/.github/workflows/groundskeeper.yml
index 68612ee..d9b5f3f 100644
--- a/.github/workflows/groundskeeper.yml
+++ b/.github/workflows/groundskeeper.yml
@@ -5,10 +5,15 @@
   workflow_call:
     inputs:
       sdk:
-        description: 'Flutter SDK channel'
+        description: 'Dart SDK version or Flutter channel'
         required: false
         type: string
         default: 'dev'
+      use-flutter:
+        description: 'Whether to use Flutter for this package'
+        required: false
+        type: boolean
+        default: false
       directory:
         description: 'The directory to tidy'
         required: false
@@ -80,10 +85,16 @@
           persist-credentials: false
 
       - uses: subosito/flutter-action@1a449444c387b1966244ae4d4f8c696479add0b2
+        if: ${{ inputs.use-flutter }}
         with:
           channel: ${{ inputs.sdk }}
           cache: true
 
+      - uses: dart-lang/setup-dart@65eb853c7ba17dde3be364c3d2858773e7144260
+        if: ${{ !inputs.use-flutter }}
+        with:
+          sdk: ${{ inputs.sdk }}
+
       - name: Resolve dependencies for firehose
         working-directory: .github/ecosystem-helper/pkgs/firehose
         run: dart pub get

pkgs/firehose/CHANGELOG.md

diff --git a/pkgs/firehose/CHANGELOG.md b/pkgs/firehose/CHANGELOG.md
index a5a2771..13ee056 100644
--- a/pkgs/firehose/CHANGELOG.md
+++ b/pkgs/firehose/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 0.13.2-wip
 
-- Use Flutter `dev` channel in `groundskeeper` workflow to support Flutter packages.
+- Support `use-flutter` option in `groundskeeper` workflow to allow tidying Flutter packages.
 - Add `--tag-prefix` option to `firehose` and `tag-prefix` input to `publish.yaml` to allow configuring the release tag prefix (defaults to `'v'`).
 - Run `pub get` before `dart format` in `groundskeeper`.
 - Add `groundskeeper` executable to format and fix packages.