Change minimum Python version to 3.9 (rucio DID finder uses this!) and do not test against earlier versions

Author: ponyisi

.github/workflows/ci.yaml

@@ -13,7 +13,7 @@ jobs:
   test:
     strategy:
       matrix:
-        python-version: ['3.7','3.8','3.9','3.10','3.11','3.12','3.13']
+        python-version: ['3.9','3.10','3.11','3.12','3.13']
     runs-on: ubuntu-latest
 
     steps:

pyproject.toml

@@ -7,7 +7,7 @@ readme = "README.md"
 packages = [{include = "servicex_codegen"}]
 
 [tool.poetry.dependencies]
-python = "^3.10"
+python = "^3.9"
 Flask = "^2.3.3"
 Flask-RESTful = "^0.3.9"
 Flask-WTF = "^1.0.1"