DOC: use reST for the readme too

IMHO reST is rendered in a nicer way than Markdown on PyPI.

It is nice to have all the documentation in the same format.

Author: dnicolodi

README.md

@@ -0,0 +1,24 @@
+.. SPDX-FileCopyrightText: 2021 The meson-python developers
+
+.. SPDX-License-Identifier: MIT
+
+meson-python
+============
+
+``meson-python`` is a Python build backend built on top of the Meson__
+build system. It enables to use Meson for the configuration and build
+steps of Python packages. Meson is an open source build system meant
+to be both extremely fast, and, even more importantly, as user
+friendly as possible. ``meson-python`` is best suited for building
+Python packages containing extension modules implemented in languages
+such as C, C++, Cython, Fortran, Pythran, or Rust. Consult the
+documentation__ for more details.
+
+Questions regarding the use of ``meson-python`` can be directed to the
+discussions__ space on GitHub. Bug reports and feature requests can be
+filed as GitHub issues__.
+
+__ https://mesonbuild.com/
+__ https://meson-python.readthedocs.io/en/latest/
+__ https://github.com/mesonbuild/meson-python/discussions/
+__ https://github.com/mesonbuild/meson-python/issues/

README.rst

@@ -15,7 +15,7 @@ requires = [
 [project]
 name = 'meson-python'
 description = 'Meson Python build backend (PEP 517)'
-readme = 'README.md'
+readme = 'README.rst'
 requires-python = '>= 3.7'
 license = { file = 'LICENSES/MIT.txt' }
 keywords = ['meson', 'build', 'backend', 'pep517', 'package']