Add SPDX-FileCopyrightText to BioLogic.py

There are additional committers who have made changes to this
file, but only adding new colIDs etc., which is not copyrightable.

Here is the corresponding git-shortlog output:

Dennis (1):
      Improved compatibility with .mpr files

Peter Attia (1):
      Update BioLogic.py

Tim (3):
      improved parsing for PEIS files
      new column types
      new column types

dennissheberla (2):
      Improved compatibility with .mpt files
      Improved compatibility with new .mpr files

nhshetty-99 (3):
      Added colIDs 74 and 462 to VMPdata_colID_dtype_map
      Changed colID 74 and 462 order from original addition
      Added column 469 to BioLogic.py

galvani/BioLogic.py

@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 """Code to read in data files from Bio-Logic instruments"""
 
+# SPDX-FileCopyrightText: 2013-2020 Christopher Kerr, "bcolsen"
+
 __all__ = ['MPTfileCSV', 'MPTfile']
 
 import re