Add pre-commit to requirements

requirements.txt

@@ -25,7 +25,7 @@ metadata_client == 3.0.8
 nbclient == 0.5.1
 nbconvert == 5.6.1
 nbformat == 5.0.7
-notebook == 6.1.5 
+notebook == 6.1.5
 numpy == 1.19.1
 prettytable == 0.7.2
 princess == 0.2
@@ -40,4 +40,5 @@ sphinx == 1.8.5
 tabulate == 0.8.6
 traitlets == 4.3.3
 unittest-xml-reporting == 3.0.2
+pre-commit==2.10.0
 .