Audit and update the pip package metadata (#3265)

Fill out the recommended `project` keys, most of which will affect the
web page that PyPI will render for the `executorch` package.

See
https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#about-your-project
for the latest guidance.

Use
https://github.com/pytorch/pytorch/blob/a21327e0b03cc18850a0608be2d9c5bd38fd4646/setup.py#L1394
as a guide for the actual values.

Add a README-wheel.md file that will be included in the wheel, and will
become the main page contents on PyPI.

Test Plan:
* Installed the package with `./install_requirements.sh`
* Looked at the files under ~/miniconda3/envs/executorch/lib/python3.10/site-packages/executorch-0.2.0a0+1a499e0.dist-info. METADATA and LICENSE both contain the new metadata.

README-wheel.md

@@ -0,0 +1,25 @@
+**ExecuTorch** is a [PyTorch](https://pytorch.org/) platform that provides
+infrastructure to run PyTorch programs everywhere from AR/VR wearables to
+standard on-device iOS and Android mobile deployments. One of the main goals for
+ExecuTorch is to enable wider customization and deployment capabilities of the
+PyTorch programs.
+
+Please visit the [ExecuTorch website](https://pytorch.org/executorch/) for
+tutorials and documentation. Here are some starting points:
+* [Getting
+  Started](https://pytorch.org/executorch/stable/getting-started-setup.html)
+  * Set up the ExecuTorch environment and run PyTorch models locally.
+* [Working with
+  local LLMs](https://pytorch.org/executorch/stable/llm/getting-started.html)
+  * Learn how to use ExecuTorch to export and accelerate a large-language model
+    from scratch.
+* [Exporting to
+  ExecuTorch](https://pytorch.org/executorch/main/tutorials/export-to-executorch-tutorial.html)
+  * Learn the fundamentals of exporting a PyTorch `nn.Module` to ExecuTorch, and
+    optimizing its performance using quantization and hardware delegation.
+* Running LLaMA on
+  [iOS](https://pytorch.org/executorch/stable/llm/llama-demo-ios.html) and
+  [Android](https://pytorch.org/executorch/stable/llm/llama-demo-android.html)
+  devices.
+  * Build and run LLaMA in a demo mobile app, and learn how to integrate models
+    with your own apps.

pyproject.toml

@@ -15,7 +15,38 @@ dynamic = [
   # setup.py will set the version.
   'version',
 ]
-# Python dependencies required for development
+description = "On-device AI across mobile, embedded and edge for PyTorch"
+readme = "README-wheel.md"
+authors = [
+  {name="PyTorch Team", email="packages@pytorch.org"},
+]
+license = {file = "LICENSE"}
+keywords = ["pytorch", "machine learning"]
+# PyPI package information.
+classifiers = [
+    # How mature is this project? Common values are
+    #   3 - Alpha
+    #   4 - Beta
+    #   5 - Production/Stable
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "Intended Audience :: Education",
+    "Intended Audience :: Science/Research",
+    "License :: OSI Approved :: BSD License",
+    "Topic :: Scientific/Engineering",
+    "Topic :: Scientific/Engineering :: Mathematics",
+    "Topic :: Scientific/Engineering :: Artificial Intelligence",
+    "Topic :: Software Development",
+    "Topic :: Software Development :: Libraries",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    "Programming Language :: C++",
+    "Programming Language :: Python :: 3",
+    # Update this as we support more versions of python.
+    "Programming Language :: Python :: 3.10",
+]
+
+# Python dependencies required for use.
+requires-python = ">=3.10"
 dependencies=[
   "expecttest",
   "flatbuffers",
@@ -32,6 +63,13 @@ dependencies=[
   "tabulate",
 ]
 
+[project.urls]
+# The keys are arbitrary but will be visible on PyPI.
+Homepage = "https://pytorch.org/executorch/"
+Repository = "https://github.com/pytorch/executorch"
+Issues = "https://github.com/pytorch/executorch/issues"
+Changelog = "https://github.com/pytorch/executorch/releases"
+
 # Tell setuptools to generate commandline wrappers for tools that we install
 # under data/bin in the pip package. This will put these commands on the user's
 # path.