build: setuptools_scm infers the version from git

I think that was the whole point of usign setuptools_scm.

MANIFEST.in

@@ -0,0 +1 @@
+include yamllint/_version.py

pyproject.toml

@@ -41,13 +41,13 @@ documentation = "https://yamllint.readthedocs.io"
 
 [build-system]
 build-backend = "setuptools.build_meta"
-requires = ["setuptools>=61"]
+requires = ["setuptools>=64", "setuptools-scm[toml]>=8"]
 
 [tool.setuptools]
 packages = ["yamllint", "yamllint.conf", "yamllint.rules"]
 
 [tool.setuptools.package-data]
 yamllint = ["conf/*.yaml"]
 
-[tool.setuptools.dynamic]
-version = {attr = "yamllint.__version__"}
+[tool.setuptools-scm]
+write_to = "yamllint/_version.py"

yamllint/__init__.py

@@ -19,12 +19,15 @@
 repetition and cosmetic problems such as lines length, trailing spaces,
 indentation, etc."""
 
+try:
+    from ._version import version as __version__
+except ImportError:
+    __version__ = "unknown version"
 
 APP_NAME = 'yamllint'
-APP_VERSION = '1.33.0'
+APP_VERSION = __version__
 APP_DESCRIPTION = __doc__
 
 __author__ = 'Adrien Vergé'
 __copyright__ = 'Copyright 2022, Adrien Vergé'
 __license__ = 'GPLv3'
-__version__ = APP_VERSION