lint: initialize mypy

Ignore the .mypy_cache/ directories.

Also use global 'ignore_missing_imports = True', otherwise we'll see
a new errors like this:

  Error: MYPY_ERROR:
  coprs_frontend/coprs/auth.py:8: mypy[error]: Skipping analyzing "ldap": module is installed, but missing library stubs or py.typed marker

  Error: MYPY_ERROR:
  coprs_frontend/coprs/auth.py:9: mypy[error]: Skipping analyzing "openid_teams.teams": module is installed, but missing library stubs or py.typed marker

  Error: MYPY_NOTE:
  coprs_frontend/coprs/auth.py:9: mypy[note]: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

We can find a better way to handle similar problems in the future.

Merges: fedora-copr#2353

Author: praiskup

.gitignore

@@ -17,6 +17,7 @@ _tmp/
 .cache/
 .pytest_cache/
 .localwrap/
+.mypy_cache/
 
 backend/docs/build
 

.mypy.ini

@@ -0,0 +1,2 @@
+[mypy]
+ignore_missing_imports = True