Remove use of pkg_resources for Python 3.12 compatibility (#14)

* Remove use of pkg_resources

* Test on 3.12

* add 'pragma: no cover' to exception

* Keep Python 3.7 compatible

.github/workflows/pytest.yml

@@ -8,7 +8,7 @@ jobs:
 
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v2

markdown_code_runner.py

@@ -44,20 +44,30 @@
 import os
 import re
 import subprocess
+import sys
 from dataclasses import dataclass, field
 from pathlib import Path
 from typing import TYPE_CHECKING, Any
 
-import pkg_resources
-
 if TYPE_CHECKING:
     try:
         from typing import Literal  # type: ignore[attr-defined]
     except ImportError:
         from typing_extensions import Literal
 
 
-__version__ = pkg_resources.get_distribution("markdown-code-runner").version
+if sys.version_info >= (3, 8):  # pragma: no cover
+    from importlib.metadata import PackageNotFoundError, version
+
+    try:
+        __version__ = version("markdown-code-runner")
+    except PackageNotFoundError:
+        __version__ = "unknown"
+else:  # pragma: no cover
+    import pkg_resources
+
+    __version__ = pkg_resources.get_distribution("markdown-code-runner").version
+
 
 DEBUG: bool = os.environ.get("DEBUG", "0") == "1"