Include french translations in list of supported languages (#591)

* Include french translations. Fixes #561

* Add instruction in README to include supported language after translation

Author: danvick

README.md

@@ -603,7 +603,18 @@ function defined in `lib/localization/form_builder_localizations.dart`. This fil
 
   ```flutter pub pub run intl_translation:generate_from_arb --output-dir=lib/l10n --no-use-deferred-loading lib/localization/form_builder_localizations.dart lib/l10n/intl_*.arb```
 
-5. Submit your PR and be of help to millions of people all over the world!
+5. Include your new language to `FormBuilderLocalization`'s supported languages. Go to `lib/localization/form_builder_localizations.dart` and include the language like so:
+
+<pre>
+<code>
+@override
+  bool isSupported(Locale locale) {
+    return ['en', 'es', <strong>'fr'</strong>].contains(locale.languageCode);
+  }
+</code>
+</pre>
+
+6. Submit your PR and be of help to millions of people all over the world!
 
 ### Coffee :-)
 If this package was helpful to you in delivering your project or you just wanna to support this

example/lib/main.dart

@@ -15,15 +15,19 @@ class MyApp extends StatelessWidget {
       theme: ThemeData(
         primarySwatch: Colors.blue,
         inputDecorationTheme: InputDecorationTheme(
-          labelStyle: TextStyle(color: Colors.purple),
+          labelStyle: TextStyle(color: Colors.blueAccent),
         ),
       ),
       localizationsDelegates: [
         FormBuilderLocalizations.delegate,
         GlobalMaterialLocalizations.delegate,
         GlobalWidgetsLocalizations.delegate,
       ],
-      supportedLocales: [Locale('en', ''), Locale('es', '')],
+      supportedLocales: [
+        Locale('en', ''),
+        Locale('es', ''),
+        Locale('fr', ''),
+      ],
       home: HomePage(),
     );
   }

lib/localization/form_builder_localizations.dart

@@ -128,7 +128,7 @@ class _FormBuilderLocalizationsDelegate
 
   @override
   bool isSupported(Locale locale) {
-    return ['en', 'es'].contains(locale.languageCode);
+    return ['en', 'es', 'fr'].contains(locale.languageCode);
   }
 
   @override