title: How to change language of Show date picker in flutter
body: <p>I would like to change the language from english to french in show date picker, Please find below the code i am using and one like which supposed to solve that but it makes the code not working for this part:</p>
  
  <pre><code>              new Step(
                title: new Text("Quelle est la date de 1er immatriculation?"),
                content: Column(
                  children: &lt;Widget&gt;[
                   Text(_datetime == null ? "Vous n'avez pas encore choisi de date" : _datetime.toString().substring(0, 10)),
  
                    RaisedButton(
                        child: Text('choisissez une date'),
                      onPressed: () {
                      showDatePicker(context: context,
                        locale : const Locale("fr","FR"),//this line making the code not working too
                        builder: (BuildContext context, Widget child) {
                          return Theme(
                            data: ThemeData.fallback(),
                            child: child,
                          );
                        },
                       // locale: const Locale('eu', 'FR'),
                        initialDate: DateTime.now(),
                          firstDate: DateTime(1920),
                            lastDate: DateTime(2100),
                        ).then((date) {
                        setState(() {
                          _datetime =  date;
                        });
                        });
                      }
                   ),
                  ],
                ),
                isActive: _currentStep &gt;= 0,
                state:
                _currentStep &gt;= 2 ? StepState.complete : StepState.disabled,
              ),
  </code></pre>