Start log lines with the Lambda request ID

[mnapoli]

Application logs had no Lambda request ID, so an error logged by the application could not be tied to its invocation: not to Bref's own lines (timeouts, Invoke Error), not to Lambda's REPORT line (duration, memory), and not to the other logs of the same request.

When $_SERVER['LAMBDA_REQUEST_ID'] is set (by Bref, on every invocation), CloudWatchFormatter now starts each line with it, like the logs of Lambda's native runtimes:

8f507cfc-8b35-4e7e-9f26-f2a3a6e7e1a2	INFO	This is a log message	{"message":"This is a log message","level":"INFO"}

Release

A major version (2.0.0): the format of the log lines changes. The bridges allow both versions (brefphp/laravel-bridge#213, brefphp/symfony-bridge#77), so applications get 2.0 on their next composer update, and can keep the previous format by requiring bref/monolog-bridge: ^1.0.