fix: remove alpha classifier (delta-io#1578)

# Description
Should the project remove the alpha classifier? or is it still
considerer an alpha project?
I am asking that because the alpha classifier currently associated with
the project might be creating some hesitation among prospective users or
partners. The alpha classifier suggests that the project is not ready
for a wider use.

If the maintainers still think that the project should be classified as
a alpha please feel free to close this PR

python/pyproject.toml

@@ -10,7 +10,6 @@ license = {file = "LICENSE.txt"}
 requires-python = ">=3.7"
 keywords = ["deltalake", "delta", "datalake", "pandas", "arrow"]
 classifiers = [
-    "Development Status :: 3 - Alpha",
     "License :: OSI Approved :: Apache Software License",
     "Programming Language :: Python :: 3 :: Only"
 ]