Merge branch 'ART_fix_plotting_macro_env' into '21.0'

Egamma ART: making python executable using /usr/bin/env

See merge request atlas/athena!11777

Former-commit-id: a0769cce198e8ac74ad85b57976daa462374eb06

Reconstruction/egamma/egammaValidation/scripts/EgammaARTmonitoring_plotsMaker.py

+#!/usr/bin/env python
 #
 # Copyright (C) 2002-2018 CERN for the benefit of the ATLAS collaboration.
 #