Require Python 3.9

Re spine-tools/Spine-Toolbox#2904

.github/workflows/run_unit_tests.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, ubuntu-22.04]
-        python-version: [3.8, 3.9, "3.10", 3.11, 3.12]
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
     steps:
     - uses: actions/checkout@v4
       with:

README.md

@@ -1,6 +1,6 @@
 # Spine Items
 
-[![Python](https://img.shields.io/badge/python-3.8%20|%203.9%20|%203.10%20|%203.11|%203.12-blue.svg)](https://www.python.org/downloads/release/python-379/)
+[![Python](https://img.shields.io/badge/python-3.9%20|%203.10%20|%203.11%20|%203.12%20|%203.13-blue.svg)](https://www.python.org/downloads/release/python-379/)
 [![Unit tests](https://github.com/spine-tools/spine-items/workflows/Unit%20tests/badge.svg)](https://github.com/spine-tools/spine-items/actions?query=workflow%3A"Unit+tests")
 [![codecov](https://codecov.io/gh/spine-tools/spine-items/branch/master/graph/badge.svg)](https://codecov.io/gh/spine-tools/spine-items)
 [![PyPI version](https://badge.fury.io/py/spine-items.svg)](https://badge.fury.io/py/spine-items)

pyproject.toml

@@ -11,11 +11,11 @@ classifiers = [
     "License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)",
     "Operating System :: OS Independent",
 ]
-requires-python = ">=3.8.1"
+requires-python = ">=3.9"
 dependencies = [
     "spinedb_api>=0.31.3",
     "spine_engine>=0.24.2",
-    # "spinetoolbox >=0.8.3",
+    # "spinetoolbox >=0.8.5",
 ]
 
 [project.urls]