docs: add note about flutter-version (#9)

* docs: add note about flutter-version

* update workflow

* temp change to diagnose build failure

* fix build

.github/workflows/main.yaml

@@ -31,6 +31,11 @@ jobs:
       - name: 🎯 Set up Flutter
         uses: subosito/flutter-action@v2
         with:
+          # TODO(bryanoltman): remove flutter-version specification once we
+          # support 3.19.4. This was added because `flutter create` creates a
+          # flutter project that requires a higher minimum Dart version than
+          # what we support.
+          flutter-version: "3.19.3"
           channel: stable
           cache: true
 
@@ -41,7 +46,7 @@ jobs:
           java-version: "17"
 
       - name: 🐦 Setup Shorebird
-        uses: shorebirdtech/setup-shorebird@v0
+        uses: shorebirdtech/setup-shorebird@v1
 
       - name: ✨ Create New Flutter Project
         run: flutter create e2e_test --empty

README.md

@@ -32,7 +32,8 @@ steps:
 
 The action takes the following inputs:
 
-- `args`: Any arguments to pass to `shorebird release`.
+- `args`: Any arguments to pass to `shorebird release`. For example, if you need
+  to use a specific version of Flutter, you can pass `--flutter-version=1.2.3`.
   - Use an extra `--` to pass arguments to Flutter (e.g. `-- --dart-define=KEY=VALUE`)
 - `platform`: Which platform to create a release for (e.g. `android` or `ios-alpha`)
 - `working-directory`: Which directory to run `shorebird release` in.