Update pyproject.toml: drop 3.8.0 support

This programmatically completes the change begun in https://github.com/databricks/databricks-sql-python/blame/ca4d7bcbcd6846bd9be1b079dcd84ce252e525b2/README.md#L16

For complicated reasons relating to package manager solving, described here https://discuss.python.org/t/requires-python-upper-limits/12663, it's not a good idea to specfy an upper cap, so I have also changed to specifying only the lower bound.

Signed-off-by: wyattscarpenter <wyattscarpenter@gmail.com>

Author: wyattscarpenter

pyproject.toml

@@ -9,7 +9,7 @@ packages = [{ include = "databricks", from = "src" }]
 include = ["CHANGELOG.md"]
 
 [tool.poetry.dependencies]
-python = "^3.8.0"
+python = ">=3.9.0"
 thrift = ">=0.16.0,<0.21.0"
 pandas = [
     { version = ">=1.2.5,<2.4.0", python = ">=3.8,<3.13" },