Fixed the --version command when installed from source (#344)

The command only worked when running it inside the git repository.

Now, it works from everywhere, and the version is constructed using
the latest git tag and the SHA of the latest commit, which may help
with further debugging in future issues.

auto_cpufreq/core.py

@@ -12,6 +12,7 @@ import time
 import click
 import warnings
 import configparser
+import pkg_resources
 from math import isclose
 from pathlib import Path
 from shutil import which
@@ -111,7 +112,7 @@ except PermissionError:
 # display running version of auto-cpufreq
 def app_version():
 
-    print("auto-cpufreq version:")
+    print("auto-cpufreq version: ", end="")
 
     # snap package
     if os.getenv("PKG_MARKER") == "SNAP":
@@ -120,19 +121,13 @@ def app_version():
     elif dist_name in ["arch", "manjaro", "garuda"]:
         aur_pkg_check = call("pacman -Qs auto-cpufreq > /dev/null", shell=True)
         if aur_pkg_check == 1:
-            print(
-                "Git commit:",
-                check_output(["git", "describe", "--always"]).strip().decode(),
-            )
+            print(pkg_resources.require("auto-cpufreq")[0].version)
         else:
             print(getoutput("pacman -Qi auto-cpufreq | grep Version"))
     else:
         # source code (auto-cpufreq-installer)
         try:
-            print(
-                "Git commit:",
-                check_output(["git", "describe", "--always"]).strip().decode(),
-            )
+            print(pkg_resources.require("auto-cpufreq")[0].version)
         except Exception as e:
             print(repr(e))
             pass

setup.py

@@ -15,7 +15,11 @@ def read(name):
 
 setup(
     name="auto-cpufreq",
-    version="1.0",
+    version_config={
+        "template": "{tag}.{sha}",
+        "dev_template": "{tag}.{sha}"
+    },
+    setup_requires=["setuptools-git-versioning"],
     description="Automatic CPU speed & power optimizer for Linux",
     long_description=readme,
     author="Adnan Hodzic",