fix: change to newly recommended tool instead of pep517.build

This was intended as a proof of concept; build seems to be the correct replacement.

See pypa/pyproject-hooks#83

.github/CONTRIBUTING.md

@@ -200,14 +200,14 @@ source, it is best to have Pip 10 on a manylinux1, macOS, or Windows system.
 You can then build the SDists, or run any procedure that makes SDists
 internally, like making wheels or installing. Since Pip itself
 does not have an `sdist` command (it does have `wheel` and `install`), you will
-need to use the `pep517` package directly:
+need to use the upcoming `build` package:
 
 ```bash
 # Normal package
-python3 -m pep517.build -s .
+python3 -m build -s .
 
 # Global extra
-PYBIND11_GLOBAL_SDIST=1 python3 -m pep517.build -s .
+PYBIND11_GLOBAL_SDIST=1 python3 -m build -s .
 ```
 
 If you want to use the classic "direct" usage of `python setup.py`, you will
@@ -232,7 +232,7 @@ When you invoke any `setup.py` command from the source directory, including
 `pip wheel .` and `pip install .`, you will activate a full source build. This
 is made of the following steps:
 
-1. If the tool is PEP 518 compliant, like `pep517.build` or Pip 10+, it will
+1. If the tool is PEP 518 compliant, like `build` or Pip 10+, it will
  create a temporary virtual environment and install the build requirements
  (mostly CMake) into it. (if you are not on Windows, macOS, or a manylinux
  compliant system, you can disable this with `--no-build-isolation` as long

.github/workflows/configure.yml

@@ -120,15 +120,15 @@ jobs:
  python-version: 3.8
 
  - name: Prepare env
- run: python -m pip install -r tests/requirements.txt pep517 twine --prefer-binary
+ run: python -m pip install -r tests/requirements.txt build twine --prefer-binary
 
  - name: Python Packaging tests
  run: pytest tests/extra_python_package/
 
  - name: Build SDist and wheels
  run: |
- python -m pep517.build -s -b .
- PYBIND11_GLOBAL_SDIST=1 python -m pep517.build -s -b .
+ python -m build -s -w .
+ PYBIND11_GLOBAL_SDIST=1 python -m build -s -w .
 
  - name: Check metadata
  run: twine check dist/*