feat: option to add a helper to lookup token

docs/cli-usage.rst

@@ -48,7 +48,7 @@ example:
 
    [elsewhere]
    url = http://else.whe.re:8080
-   private_token = CkqsjqcQSFH5FQKDccu4
+   private_token = lookup: pass show path/to/password
    timeout = 1
 
 The ``default`` option of the ``[global]`` section defines the GitLab server to

gitlab/config.py

@@ -17,6 +17,7 @@
 
 import os
 import configparser
+import subprocess
 from typing import List, Optional, Union
 
 from gitlab.const import USER_AGENT
@@ -150,6 +151,16 @@ def __init__(
         except Exception:
             pass
 
+        for attr in ("job_token", "http_password", "private_token", "oauth_token"):
+            value = getattr(self, attr)
+            prefix = "lookup:"
+            if isinstance(value, str) and value.lower().strip().startswith(prefix):
+                helper = value[len(prefix) :].strip()
+                value = (
+                    subprocess.check_output(helper, shell=True).decode("utf-8").strip()
+                )
+                setattr(self, attr, value)
+
         self.api_version = "4"
         try:
             self.api_version = self._config.get("global", "api_version")