Introduce pre-commit-hooks hook (#202)

• Introduce pre-commit-hooks hook
• Introduce mdformat hook
• Use pre-commit run -a short option
• Set job for minor pre-commit hooks

Close #202 (closed).

tests/key/test_ascii_armor.py

@@ -39,7 +39,7 @@ Hello world !
 Héhé ;-)
 
 This is a utf-8 message...
-       
+
        """
         # create encrypted and signed ascii armor message
         encrypted_and_signed_aa_message = AsciiArmor.create(