update version numbers for 6.0.0 release

Author: C.A.P. Linssen

pynestml/__init__.py

@@ -19,7 +19,7 @@
 # You should have received a copy of the GNU General Public License
 # along with NEST.  If not, see <http://www.gnu.org/licenses/>.
 
-__version__ = "5.3.0-post-dev"
+__version__ = "6.0.0"
 
 __all__ = ['cocos',
            'codegeneration',

setup.py

@@ -39,7 +39,7 @@
 
 setup(
     name="NESTML",
-    version="5.3.0-post-dev",
+    version="6.0.0",
     description="NESTML is a domain specific language that supports the specification of neuron models in a"
                 " precise and concise syntax, based on the syntax of Python. Model equations can either be given"
                 " as a simple string of mathematical notation or as an algorithm written in the built-in procedural"