Update pandas from 2.3.0 to 2.3.1

Author: pyup-bot

extra_requirements.txt

@@ -3,7 +3,7 @@
 # we use the latest version to see any problems with new versions
 pandas==1.3.5; python_version == '3.7' # pyup: ignore
 pandas==2.0.3; python_version == '3.8' # pyup: ignore
-pandas==2.3.0; python_version > '3.8'
+pandas==2.3.1; python_version > '3.8'
 xlrd==2.0.2
 openpyxl==3.1.3; python_version == '3.7' # pyup: ignore
 openpyxl==3.1.5; python_version > '3.7'