Move the setuptools settings into pyproject.toml

Except for `zip_safe`. It's not especially relevant nowadays, so just
delete it.

pyproject.toml

@@ -41,6 +41,32 @@ Changelog = "https://pip.pypa.io/en/stable/news/"
 requires = ["setuptools>=67.6.1", "wheel"]
 build-backend = "setuptools.build_meta"
 
+[tool.setuptools]
+package-dir = {"" = "src"}
+include-package-data = false
+
+[tool.setuptools.dynamic]
+version = {attr = "pip.__version__"}
+
+[tool.setuptools.packages.find]
+where = ["src"]
+exclude = ["contrib", "docs", "tests*", "tasks"]
+
+[tool.setuptools.package-data]
+"pip" = ["py.typed"]
+"pip._vendor" = ["vendor.txt"]
+"pip._vendor.certifi" = ["*.pem"]
+"pip._vendor.requests" = ["*.pem"]
+"pip._vendor.distlib._backport" = ["sysconfig.cfg"]
+"pip._vendor.distlib" = [
+    "t32.exe",
+    "t64.exe",
+    "t64-arm.exe",
+    "w32.exe",
+    "w64.exe",
+    "w64-arm.exe",
+]
+
 [tool.towncrier]
 # For finding the __version__
 package = "pip"

setup.py

@@ -1,49 +1,8 @@
-import os
 import sys
 
-from setuptools import find_packages, setup
-
-
-def read(rel_path: str) -> str:
-    here = os.path.abspath(os.path.dirname(__file__))
-    # intentionally *not* adding an encoding option to open, See:
-    #   https://github.com/pypa/virtualenv/issues/201#issuecomment-3145690
-    with open(os.path.join(here, rel_path)) as fp:
-        return fp.read()
-
-
-def get_version(rel_path: str) -> str:
-    for line in read(rel_path).splitlines():
-        if line.startswith("__version__"):
-            # __version__ = "0.9"
-            delim = '"' if '"' in line else "'"
-            return line.split(delim)[1]
-    raise RuntimeError("Unable to find version string.")
-
+from setuptools import setup
 
 setup(
-    version=get_version("src/pip/__init__.py"),
-    package_dir={"": "src"},
-    packages=find_packages(
-        where="src",
-        exclude=["contrib", "docs", "tests*", "tasks"],
-    ),
-    include_package_data=False,
-    package_data={
-        "pip": ["py.typed"],
-        "pip._vendor": ["vendor.txt"],
-        "pip._vendor.certifi": ["*.pem"],
-        "pip._vendor.requests": ["*.pem"],
-        "pip._vendor.distlib._backport": ["sysconfig.cfg"],
-        "pip._vendor.distlib": [
-            "t32.exe",
-            "t64.exe",
-            "t64-arm.exe",
-            "w32.exe",
-            "w64.exe",
-            "w64-arm.exe",
-        ],
-    },
     entry_points={
         "console_scripts": [
             "pip=pip._internal.cli.main:main",
@@ -51,5 +10,4 @@ setup(
             "pip{}.{}=pip._internal.cli.main:main".format(*sys.version_info[:2]),
         ],
     },
-    zip_safe=False,
 )