[fix] engine yacy: update list of base URLs

https://search.lomig.me
  Poor results / tested `!yacy :en hello` and got zero results

https://yacy.ecosys.eu
  Slow response (> 6sec for trivial search terms)

https://search.webproject.link
  Dead instance / URL offline

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/yacy.py

@@ -118,6 +118,8 @@ def _base_url() -> str:
     url = engines['yacy'].base_url  # type: ignore
     if isinstance(url, list):
         url = random.choice(url)
+    if url.endswith("/"):
+        url = url[:-1]
     return url