add code to get version, fix OS classifier in pyproject.toml, don't w…

…rite _version.py file

gstat_exporter.py

@@ -1,6 +1,14 @@
 from prometheus_client import start_http_server, Gauge  # type: ignore
 from subprocess import Popen, PIPE
 from typing import Dict
+from importlib.metadata import PackageNotFoundError, version
+
+# get version
+try:
+    __version__ = version("gstat_exporter")
+except PackageNotFoundError:
+    # package is not installed, version unknown
+    __version__ = "0.0.0"
 
 
 def get_deviceinfo(name: str) -> Dict[str, str]:

pyproject.toml

@@ -11,7 +11,7 @@ authors = [
 classifiers = [
     "License :: OSI Approved :: BSD License",
     "Programming Language :: Python :: 3",
-    "Operating System :: FreeBSD",
+    "Operating System :: POSIX :: BSD :: FreeBSD",
 ]
 
 dependencies = [
@@ -35,4 +35,3 @@ dev = ["twine == 4.0.2", "pre-commit == 3.5.0", "setuptools-scm == 8.0.4", "buil
 homepage = "https://github.com/tykling/gstat_exporter"
 
 [tool.setuptools_scm]
-version_file = "_version.py"