chore: fix broken pre commit hook with python 3 7 (#953)

* bump pre-commit python to 3.9

* try another ignore syntax

* remove ignore directive

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Co-authored-by: CircleCI <[email protected]>

Author: harelmo-lumigo

.pre-commit-config.yaml

@@ -3,7 +3,7 @@ repos:
     rev: 20.8b1
     hooks:
     - id: black
-      language_version: python3.7
+      language_version: python3.9
       exclude: '(src/lumigo_opentelemetry/external/.*|src/test/integration/grpcio/app/helloworld_pb2.*)'
       additional_dependencies: ['click==8.0.4']