Updated composer.json to latest version of rollback

[earnaway]

Updated rollbar/rollbar to 0.16

[GiamPy5]

Currently the newest rollbar version gets installed already, thanks to the Tilde operator.

The ~ operator is best explained by example: ~1.2 is equivalent to >=1.2 <2.0.0, while ~1.2.3 is equivalent to >=1.2.3 <1.3.0. As you can see it is mostly useful for projects respecting semantic versioning. A common usage would be to mark the minimum minor version you depend on, like ~1.2 (which allows anything up to, but not including, 2.0). Since in theory there should be no backwards compatibility breaks until 2.0, that works well. Another way of looking at it is that using ~ specifies a minimum version, but allows the last digit specified to go up.

[jenssegers]

@GiampaoloFalqui is right :)