updated requirements to include modern version of pandas

requirements.txt

@@ -8,7 +8,7 @@ joblib==0.14.1
 kiwisolver==1.1.0
 matplotlib==3.1.3
 numpy==1.18.1
-pandas==1.0.1
+pandas==1.1.0
 psycopg2-binary==2.8.4
 pyparsing==2.4.6
 python-dateutil==2.8.1