conda pkgs for reportengine

Created by: tgiani

As mentioned in #651 when installing the nnpdf dependencies in a conda environment using

conda install --only-deps nnpdf

the reportengine version which is installed is not the latest one. Similarly when running

conda update reportengine 

nothing happens. However, if in a new environment I run

conda install reportengine -c https://packages.nnpdf.science/conda

it does install the latest version.