extension join-adjascent: adapt formatting of datetime columns

extensions/join-adjascent

@@ -41,8 +41,10 @@ def _main():
             remove_tags=selected_tags,
         )
     ).assign(
-        start=lambda df: df["start"].dt.tz_convert("Europe/Vienna"),
-        end=lambda df: df["end"].dt.tz_convert("Europe/Vienna"),
+        start=lambda df: df["start"]
+        .dt.tz_convert("Europe/Vienna")
+        .dt.strftime("%Y-%m-%d %H:%M"),
+        end=lambda df: df["end"].dt.tz_convert("Europe/Vienna").dt.strftime("%H:%M"),
     )
     print(recordings)