feat: add self-update functionality

- add new configuration option `self-update` to enable automatic updates
- implement `do_selfupdate` function in `lib/helper.py` to perform the update
- call `do_selfupdate` in `dc-ops` if `self-update` is enabled

🤖

lib/helper.py

@@ -1,9 +1,26 @@
 import logging as log
 import subprocess
+import sys
+from pathlib import Path
 
 import git
 
 
+def do_selfupdate():
+    """perform git pull on script's base directory"""
+    repo_path = Path(sys.argv[0]).parent.absolute()
+    repo = git.Repo(repo_path)
+    try:
+        pull_res = repo.remotes.origin.pull()[0]
+    except git.exc.GitCommandError as e:
+        log.error(str(e))
+        return
+    if pull_res.old_commit:
+        log.info("selfupdate: successfully updated myself - exiting")
+        sys.exit(0)
+    log.info("selfupdate: no updates found for myself")
+
+
 def run_subprocess(command: str, workdir: str) -> bool:
     """execute subprocess and print output