Added latest changes in the CHANGELOG

Author: RemiLehe

CHANGELOG.md

@@ -9,3 +9,4 @@ This is version `0.2.0` of openPMD-viewer. A number of minor changes and fixes h
 - The data reader can now support `macroWeighted` quantities. As consequence, output files from [PIConGPU](https://github.com/ComputationalRadiationPhysics/picongpu) can now be correctly read.
 - The package does not assume anymore that all species contain the same particle quantities. For instance, the package will support a file that contains the positions of ions, and the positions, momenta and weighting of electrons. As part of this, the attribute `OpenPMDTimeSeries.avail_ptcl_quantities` has been replaced by a dictionary `OpenPMDTimeSeries.avail_record_components`.
 - This release introduces automatic PEP8 verification as part of the automatic tests that are run on Travis CI (see CONTRIBUTING.md).
+- The evaluation of the waist and duration of the laser is now based on Gaussian fit of the transverse and longtudinal profile respectively.