Fix error message in case of missing name

[brodycj]

While testing something else in my work area I mistakenly tried the following command with the module package name missing in the master branch (at 4f4c563):

./bin/cli.js --generate-example --example-react-native-version react-native@0.60

which is equivalent to the following command with global installation:

create-react-native-module --generate-example --example-react-native-version react-native@0.60

It gave me the following output:

/Users/brodybits/dev/create-react-native-module/lib/cli-command.js:44
    const name = args[0];
                     ^

TypeError: Cannot read property '0' of undefined
    at Object.action (/Users/brodybits/dev/create-react-native-module/lib/cli-command.js:44:22)
    at Command.programAction (/Users/brodybits/dev/create-react-native-module/lib/cli-program.js:17:13)
    at Command.listener [as _actionHandler] (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:408:31)
    at Command._parseCommand (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:909:14)
    at Command.parse (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:712:10)
    at Object.<anonymous> (/Users/brodybits/dev/create-react-native-module/lib/cli-program.js:32:9)
    at Module._compile (internal/modules/cjs/loader.js:1158:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1178:10)
    at Module.load (internal/modules/cjs/loader.js:1002:32)
    at Function.Module._load (internal/modules/cjs/loader.js:901:14)

At the recent 0.16.0 tag it would give me the following output:

    throw new TypeError("Please write your library's name");
    ^

TypeError: Please write your library's name
    at module.exports (/Users/brodybits/dev/create-react-native-module/lib/normalized-options.js:16:11)
    at Object.func (/Users/brodybits/dev/create-react-native-module/lib/cli-command.js:56:27)
    at Command.runAction (/Users/brodybits/dev/create-react-native-module/lib/cli-program.js:14:13)
    at Command.listener (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:291:8)
    at Command.emit (events.js:311:20)
    at Command.parseArgs (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:686:12)
    at Command.parse (/Users/brodybits/dev/create-react-native-module/node_modules/commander/index.js:459:21)
    at Object.<anonymous> (/Users/brodybits/dev/create-react-native-module/lib/cli-program.js:29:9)
    at Module._compile (internal/modules/cjs/loader.js:1158:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1178:10)

---

P.S. Part of the cause is that this case was not properly covered by unit or integration testing.