v0.4.0: Merge pull request #26 from tvogels/poetry-and-typing

This Release technically contains breaking changes (e.g. changing some raised Exception to ValueError), but I don't believe they would meaningfully impact any existing code.

Changes

• Added type hints.
• Explicitly depends on OpenEXR >=3.2.3, which has many prebuilt wheels, significantly simplifying the install process.
• Changed bare-exceptions to more specific exceptions like ValueError or TypeError.
• Remove spurious print statements, information is now included in raised exceptions.
• InputFile.describe_channels() now returns string data instead of printing it.
• Now works with pathlib.Path paths.
• Update deprecated np.tostring to np.tobytes in #18.
• Added contextmanager (with pyexr.open(...) as f:)and close() methods to InputFile by @r1cc4rdo in #23
• Allow the writing of additional metadata via extra_headers parameter by @NinjaCats in #20

Internal Changes

• Use Poetry.
• Add Github Actions.
• Add linting (black) and other code quality checks via pre-commit.
• Add unit tests.
• Add codecoverage