Fix mypy no implicit reexports errors

Just for the future reference used this asnwer from so
https://stackoverflow.com/questions/79371127/module-does-not-explicitly-export-attribute-attr-defined

Author: kbaikov

mypy.ini

@@ -3,6 +3,7 @@
 warn_unused_configs = True
 warn_redundant_casts = True
 warn_unused_ignores = True
+no_implicit_reexport = True
 
 [mypy-test.*]
 disallow_untyped_defs = True

pygit2/errors.py

@@ -27,6 +27,8 @@
 from ._pygit2 import GitError
 from .ffi import C, ffi
 
+__all__ = ['GitError']
+
 value_errors = set([C.GIT_EEXISTS, C.GIT_EINVALIDSPEC, C.GIT_EAMBIGUOUS])
 
 

pygit2/ffi.py

@@ -26,3 +26,5 @@
 # Import from pygit2
 from ._libgit2 import ffi  # noqa: F401
 from ._libgit2 import lib as C  # type: ignore # noqa: F401
+
+__all__ = ['C', 'ffi']