Deprecated attribute used - code update for csv2rdf.py

[ShivikaPrasanna]

Input:
ID, Year, Name
0, 2000, ABC
1, 2000, ABC
1, 2001, DEF
2, 2005, XYZ

Env:
Python 3.8.3
Pandas 1.0.5
rdflib 5.0.0
python-slugify 4.0.1
macOS 11.2.1

Output:
Traceback (most recent call last):
File "CSV2RDF/csv2rdf/csv2rdf.py", line 135, in
converter.convert_to_rdf(DATA_NAMESPACE, SCHEMA_NAMESPACE, INSTANCE_CLASS)
File "CSV2RDF/csv2rdf/csv2rdf.py", line 63, in convert_to_rdf
value = self.table.ix[index][column]
File "/Users/../opt/anaconda3/lib/python3.8/site-packages/pandas/core/generic.py", line 5274, in getattr
return object.getattribute(self, name)
AttributeError: 'DataFrame' object has no attribute 'ix'