Require Python ^ 3.9; remove Python 3.8 from CI matrix and from black…

… `target-version`s, as black no longer supports it.

.github/workflows/python-package.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
     - name: Check out repository

pyproject.toml

@@ -8,7 +8,7 @@ readme = 'README.md'
 repository = 'https://github.com/Olen/Spond'
 
 [tool.poetry.dependencies]
-python = "^3.8"
+python = "^3.9"
 aiohttp = "^3.8.5"
 
 [tool.poetry.group.dev.dependencies]
@@ -19,7 +19,7 @@ pytest-asyncio = "^0.23.6"
 
 [tool.black]
 line-length = 88
-target-version = ['py38', 'py39', 'py310', 'py311', 'py312', 'py313']
+target-version = ['py39', 'py310', 'py311', 'py312', 'py313']
 
 [tool.isort]
 profile = "black"