Improve file identification for mypy

[maxi297]

What

The current mypy script flags any file that is different from master. When there is a change to a file on master and you haven't merge master into your branch, it'll prevent you from merging even though there are no conflicts.

Here is an example where I was doing changes to the CATs but got a CI failure:

(.venv) python% git diff --name-only --relative --diff-filter=d remotes/origin/master -- . ':(exclude)unit_tests' | grep -E '\.py$'
airbyte_cdk/connector_builder/message_grouper.py
airbyte_cdk/sources/declarative/models/declarative_component_schema.py
airbyte_cdk/sources/declarative/requesters/http_requester.py
airbyte_cdk/sources/declarative/retrievers/simple_retriever.py
airbyte_cdk/sources/file_based/config/file_based_stream_config.py
airbyte_cdk/sources/file_based/file_types/avro_parser.py
airbyte_cdk/sources/message/repository.py
airbyte_cdk/sources/streams/core.py
airbyte_cdk/sources/streams/http/http.py
airbyte_cdk/sources/streams/http/rate_limiting.py
setup.py

How

Concatenate the following commands:

• git diff --name-only --relative ':(exclude)unit_tests': unstaged files
• git diff --name-only --staged --relative ':(exclude)unit_tests';: staged files
• git diff --name-only master... --relative ':(exclude)unit_tests'; }: commit files

After that, grep and filter out duplicates

[girarda]