fix: remove deprecated distutils (#604)

dockertidy/utils.py

@@ -1,7 +1,29 @@
 #!/usr/bin/env python3
 """Global utility methods and classes."""
 
-from distutils.util import strtobool
+
+def strtobool(value):
+    """Convert a string representation of truth to true or false."""
+
+    _map = {
+        "y": True,
+        "yes": True,
+        "t": True,
+        "true": True,
+        "on": True,
+        "1": True,
+        "n": False,
+        "no": False,
+        "f": False,
+        "false": False,
+        "off": False,
+        "0": False
+    }
+
+    try:
+        return _map[str(value).lower()]
+    except KeyError as err:
+        raise ValueError(f'"{value}" is not a valid bool value') from err
 
 
 def to_bool(string):