Add a new branch cut GH workflow, and adopt setuptools-scm for version control (#15985)

python/pyproject_cpu.toml

@@ -1,11 +1,11 @@
 # https://docs.sglang.io/platforms/cpu_server.html
 [build-system]
-requires = ["setuptools>=61.0", "wheel"]
+requires = ["setuptools>=61.0", "setuptools-scm>=8.0", "wheel"]
 build-backend = "setuptools.build_meta"
 
 [project]
 name = "sglang"
-version = "0.5.6.post2"
+dynamic = ["version"]
 description = "SGLang is a fast serving framework for large language models and vision language models."
 readme = "README.md"
 requires-python = ">=3.10"
@@ -129,6 +129,10 @@ exclude = [
   "tests*",
 ]
 
+[tool.setuptools_scm]
+root = ".."
+version_file = "sglang/_version.py"
+
 [tool.codespell]
 ignore-words-list = "ans, als, hel, boostrap, childs, te, vas, hsa, ment"
 skip = "*.json,*.jsonl,*.patch,*.txt"