Update logger format to include timestamps

[juliojordan]

What does this PR do? What is the motivation?

Running the current example code yields this output.

{"level":"info","message":"Hello simple log!"}
{"color":"blue","level":"info","message":"Hello log with metas"}

By applying this change, the output will include the timestamp as expected.

Check the content of the <FILE_NAME>.log file to confirm that Winston is logging in JSON:

{"level":"info","message":"Hello simple log!","timestamp":"2015-04-23T16:52:05.337Z"}
{"color":"blue","level":"info","message":"Hello log with metas","timestamp":"2015-04-23T16:52:05.339Z"}

Merge instructions

Merge readiness:

• Ready for merge

Additional notes

[maycmlee]

Thanks @juliojordan for opening this PR! We'll take a look and be back in touch.