corrected date to march not may...

tools/tascalc/cov.py

@@ -267,7 +267,7 @@ def check_versions():
 # main
 #
 if __name__ == "__main__":
-	print("This is a covariance matrix calculator using MC events, written by T. Weber <tweber@ill.fr>, 30 May 2019.\n")
+	print("This is a covariance matrix calculator using MC events, written by T. Weber <tweber@ill.fr>, 30 March 2019.\n")
 	check_versions()
 
 	import argparse as arg