Doesn't handle german Umlaute

[BluePalmTree]

Hello,

I really like the packe. It works really well, but I noticed an issue with german Umlaute (ä,ö,ü). For example if we execute the following Statement:

flutter pub global run rename setAppName --targets ios,android --value "Häuschen App"

It renames the apps to:

<application
        android:label="Häuschen App"        
        android:name="${applicationName}"
        android:icon="@mipmap/ic_launcher">

and

<key>CFBundleDisplayName</key>
<string>Häuschen App</string>
<key>CFBundleName</key>
<string>Häuschen App</string>

Is there a way to escape these charactors or maybe pass an encoding?