Minor cleanup of CHANGES file (#2327)

* SUBMITTING no longer needed; see CONTRIBUTING.md
* simplify CHANGES file

CHANGES

@@ -1,34 +1,10 @@
-CHANGES in GRASS GIS 8.x compared to GRASS GIS 7.x
-
-Efforts have concentrated on making the user experience even better,
-providing many new useful additional functionalities to modules and
-further improving the graphical user interface. The new graphical user
-interface with entirely rewritten startup sequence.
+CHANGES in GRASS GIS 8.x
 
 https://trac.osgeo.org/grass/wiki/Grass8/NewFeatures80
+https://trac.osgeo.org/grass/wiki/Grass8/NewFeatures82
 
-See list of releases with changelog at
-https://trac.osgeo.org/grass/wiki/Release
-
-
-CHANGES in GRASS GIS 7.0 compared to GRASS GIS 6.x
-
-The graphical user interface based on wxPython (introduced in GRASS GIS 
-6.4) has been enriched with many new features in order to make complex 
-GIS operations available as simple as possible. The old Tcl/Tk based 
-GUI has been dropped. Relevant new features are available in the core 
-system, among the most important the  new Python interface to the C 
-library. This new feature permits Python developers to create new 
-modules in a simple way while at the same time creating powerful and 
-fast modules. Furthermore, the vector library was particularly improved 
-to make it faster and more efficient with support of  huge files. This 
-required a  easy to manage topology format update including a new 
-spatial index. Finally, there are a series of new modules to analyse 
-raster and vector data; some of the already existing modules were 
-improved and made faster (some even 1000 x faster). 
-
-In total, more than 10,000 changes have been implemented in GRASS GIS 7.0.0
-with respect to GRASS GIS 6.4.x
+List of releases:
 
-For details, please refer to this Web page:
-http://trac.osgeo.org/grass/wiki/Grass7/NewFeatures
+- GitHub list: https://github.com/OSGeo/grass/releases
+- Overview list: https://trac.osgeo.org/grass/wiki/Release
+- History: https://grass.osgeo.org/home/history/releases/ (starting 1984!)

NEWS

@@ -2,6 +2,7 @@ NEWS
 
 GRASS GIS 8
  o https://trac.osgeo.org/grass/wiki/Grass8/NewFeatures80
+ o https://trac.osgeo.org/grass/wiki/Grass8/NewFeatures82
 
 GRASS GIS 7
  o https://trac.osgeo.org/grass/wiki/Grass7/NewFeatures78