Drop Python 3.7 support

Update minimum Python version to 3.8:
- pyproject.toml: requires-python >= 3.8
- GitHub Actions: test on 3.8-3.12
- Black target-version updated
- MyPy python_version updated

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: behdad

.github/workflows/ci.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
     - uses: actions/checkout@v4

pyproject.toml

@@ -7,7 +7,7 @@ name = "packtab"
 version = "0.4.0"
 description = "Unicode (and other integer) table packer"
 readme = "README.md"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 license = {text = "Apache Software License 2.0"}
 authors = [
     {name = "Behdad Esfahbod", email = "behdad@behdad.org"}
@@ -17,7 +17,6 @@ classifiers = [
     "Intended Audience :: Developers",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
@@ -48,7 +47,7 @@ include = ["packTab*"]
 
 [tool.black]
 line-length = 88
-target-version = ['py37', 'py38', 'py39', 'py310', 'py311']
+target-version = ['py38', 'py39', 'py310', 'py311', 'py312']
 include = '\.pyi?$'
 extend-exclude = '''
 /(
@@ -65,7 +64,7 @@ extend-exclude = '''
 '''
 
 [tool.mypy]
-python_version = "3.7"
+python_version = "3.8"
 warn_return_any = true
 warn_unused_configs = true
 disallow_untyped_defs = false