Deal with case of missing PATH

src/vorta/borg/borg_job.py

@@ -207,7 +207,8 @@ def prepare_bin(cls):
         # More info at https://github.com/borgbase/vorta/issues/2100
         # Set the path to also find homebrew installs of Borg, and avoid falling back to the embedded binary.
         if sys.platform == 'darwin':
-            os.environ["PATH"] += ":/opt/homebrew/bin:/usr/local/bin"
+            current_path = os.environ.get("PATH", "")
+            os.environ["PATH"] = f"{current_path}:/opt/homebrew/bin:/usr/local/bin"
         # Now continue looking for the borg binary to use
         borg_in_path = shutil.which('borg')