Add '--name' flag to 'netlify functions:create'

An alternative to passing the first positional argument that
matches the style described in the message returned by
'netlify functions'

src/commands/functions/create.js

@@ -20,7 +20,7 @@ exports.handler = async function(event, context) {
 class FunctionsCreateCommand extends Command {
   async run() {
     const { flags, args } = this.parse(FunctionsCreateCommand)
-    const { name } = args
+    const name = flags.name || args.name
     const { config } = this.netlify
 
     this.log(`Creating function ${name}`)
@@ -70,6 +70,7 @@ FunctionsCreateCommand.description = `create a new function locally
 FunctionsCreateCommand.examples = ['netlify functions:create hello-world']
 
 FunctionsCreateCommand.flags = {
+  name: flags.string({ char: 'n', description: 'function name' }),
   functions: flags.string({ char: 'f', description: 'functions folder' }),
   dir: flags.boolean({
     char: 'd',