Add more typing to the codebase and various fixes.

[sodul]

• ensure the Makefile will behave more consistently across machines by setting the shell to Bash.
• update the coverage.py configuration in pyproject.toml to exclude if TYPE_CHECKING: blocks.
• fix potential bugs in the loader.
• fix default global kwargs dict in process.py.

[sodul]

The coverage reports are broken somehow (reported as zero coverage), but only over GH Actions. Locally it seems to work fine either on macOS or through a Linux container:

> ./g -rv -s 9 ./green
...................................................................................................................s....................................................................................................................s

Skipped green.test.test_output.TestGreenStream.testDisableWindowsFalse - Colorama won't strip ANSI unless running on Windows

Skipped green.test.test_windows.TestWindows.test_colorOutput - This test is for windows-specific behavior.

Name                     Stmts   Miss  Cover   Missing
------------------------------------------------------
green/__init__.py            2      2     0%   1-3
green/__main__.py            3      3     0%   1-5
green/cmdline.py            59     12    80%   87-101
green/command.py            39      0   100%
green/config.py              2      2     0%   4-8
green/djangorunner.py       61      0   100%
green/examples.py           26     26     0%   1-68
green/exceptions.py          3      0   100%
green/junit.py             120      0   100%
green/loader.py            264      0   100%
green/output.py            101      0   100%
green/process.py            55      0   100%
green/result.py            405      1    99%   333
green/runner.py             73      0   100%
green/suite.py             122     13    89%   96, 100-103, 115-120, 126-129
green/test/__init__.py       0      0   100%
green/version.py             0      0   100%
------------------------------------------------------
TOTAL                     1335     59    96%

Ran 233 tests in 5.606s using 9 processes

OK (passes=231, skips=2)

I'll try to get that fixed as a separate issue.

[coveralls]

coverage: 0.0%. remained the same when pulling 842242b038baac61f1843804fb779be622f8ee78 on clumio-oss:typing into 2301a7f497eda9559dfbe347fde92662a8fb9699 on CleanCut:main.