[GRASS-PSC] Amendment to the announcement concerning lists of contributors

[Chief Return Officer (CRO) - GRASS GIS election 2020]

Hello PSC

Just to note that after a request by Markus I will add the following 
lists of contributors to those already announced.

1) GRASS GIS Addon contributors:
https://github.com/OSGeo/grass-addons/blob/master/contributors.csv

all those who contributed through merged pull requests which are project 
contributions:

2) https://github.com/OSGeo/grass/graphs/contributors
3) https://github.com/OSGeo/grass-addons/graphs/contributors


/H.