increase version to 3.1.4 and update CHANGELOG

Author: mattmilten

CHANGELOG.md

@@ -3,10 +3,13 @@
 ## Unreleased
 ### Added
 ### Fixed
-- allow NULL solutions to query LP solutions in the correct solving stage
 ### Changed
 ### Removed
 
+## 3.1.4 - 2021-04-25
+### Fixed
+- check for correct stage when querying solution values (raise warning otherwise)
+
 ## 3.1.3 - 2021-04-23
 ### Fixed
 - check for NULL pointers when creating Solution objects (will return None): [#494](https://github.com/scipopt/PySCIPOpt/pull/494)

src/pyscipopt/__init__.py

@@ -1,4 +1,4 @@
-__version__ = '3.1.3'
+__version__ = '3.1.4'
 
 # required for Python 3.8 on Windows
 import os