ops: update pre-commit config to use fine grain cache for mypy (#996)

Author: georgeh0

.pre-commit-config.yaml

@@ -49,7 +49,7 @@ repos:
 
         - id: mypy-check
           name: mypy type check
-          entry: mypy
+          entry: mypy --cache-fine-grain
           language: system
           types: [python]
           pass_filenames: false