[Chore] add initial support for PEP517 builds

[abn]

Motivation

An issue was raised at python-poetry/poetry#9707 indicating that PEP517 builds of this project was failing due to missing build system requirement declaration.

Modification

This change adds initial pyproject.toml file to allow PEP517 builds.

Use cases

The project can now be build correctly by PEP517 front ends. For example, with this change the following command will work.

python3.8 -m pip wheel 'git+https://github.com/open-mmlab/mmagic.git'

You can test the changes using the following command.

python3.8 -m pip wheel 'git+https://github.com/open-mmlab/mmagic.git@refs/pull/2154/head'

Checklist

Submitting this pull request means that,

Before PR:

• I have read and followed the workflow indicated in the CONTRIBUTING.md to create this PR.
• Pre-commit or linting tools indicated in CONTRIBUTING.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with some of those projects.
• CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

All committers have signed the CLA.

[abn]

The lint failures seem to be originating from a file that was not touched in the change.