Update changelog for version 3.1.1 changes

Author: azarz

changelog.md

@@ -1,10 +1,13 @@
 # CHANGELOG
 
+## 3.1.1
+CHANGED:
+- database connection managment now handled by separate class, that implements retries and timeout
+
 ## 3.1.0
 ADDED:
 - fields vla_par_defaut, cout_penalites, vehicule_leger_interdit, cout_vehicule_prioritaire 
 
-
 ## 3.0.0
 REMOVED:
 - remove field "bade_cyclable" after its removal in BD TOPO