Error message for Sample should be explicit in column name for publication year

[Rensvandeschoot]

See the feedback provided by @RiannevanderFeen in asreview/asreview#1853 (reply in thread)

 it says the publication year column is missing.

File "(...)Python312\site-packages\asreviewcontrib\datatools\sample.py", line 13, in sample
raise ValueError(f"• The input file should have a {year_column} column.")
ValueError: • The input file should have a publication_year column.

It seems like I fixed this by changing the "year" column to "publication_year" in the Excel file.

We could improve the error message or add year as a recognizable column name.