When creating a new project, the build fails with an error similar to:
"versionCode not found. Define flutter.versionCode in the local.properties file."
This puts developers in the untenable situation of having to edit a file with local paths, but being unable to check it in.
This changes the templates to default to using versionCode 1 and version "1.0" if they are not defined in the local.properties file.
Fixes#18983.
