Update documentation for checks in README
The description of the checks functionality is updated according to changes in lhcb-dpa/analysis-productions/lbapcommon!31 (merged) and lhcb-dpa/analysis-productions/lbaplocal!26 (merged) .
DPA task https://gitlab.cern.ch/lhcb-dpa/project/-/issues/146 on documentation.
Edited by Giulia Tuci