fix(swift): add missing comma in Setup code example

[blumamir]

I followed the swift instructions from the OpenTelemetry website and there is a comma missing in the Setup example:

From the swift docs:

You call the greet(person:alreadyGreeted:) function by passing it both a String argument value labeled person and a Bool argument value labeled alreadyGreeted in parentheses, separated by commas

According to the swift website, when calling a function, there should be a comma

[svrnm]

Thanks!