Excluding validation error type `PR10` from code base

[stijnvanhoey]

Problem description

In order to have a continuous check by the CI on validation error PR10, tackling them from the current code base enables the addition to the CI for automated testing in the future.

After checking an overview of the errors (all credits to @datapythonista for the introduction during europandas sprint), the PR10 has just 3 occurrences, so tackling them should be feasible during the sprint.

	deprecated	section	type
pandas.set_option	0	Working with options	CallableDynamicDoc
pandas.ExcelWriter	0		ABCMeta
pandas.core.groupby.DataFrameGroupBy.boxplot	0	Computations / Descriptive Stats	function

Todo:

• get rid of the errors in the code base
• update the code_check.sh script to take into account the PR10 type of errors

[victormoron]

I'll take it