update readme
update readme

updated the angular version we support.
AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js,AzureAD/microsoft-authentication-library-for-js