[pylint] Pylint 2.10 - fix use-list-literal & use-dict-literal

Pylint 2.10 added new default checks [1]:

use-list-literal
  Emitted when list() is called with no arguments instead of using []

use-dict-literal
  Emitted when dict() is called with no arguments instead of using {}

[1] https://pylint.pycqa.org/en/latest/whatsnew/2.10.html

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

searx/engines/google_images.py

@@ -66,7 +66,7 @@ filter_mapping = {
 def scrap_out_thumbs(dom):
     """Scrap out thumbnail data from <script> tags.
     """
-    ret_val = dict()
+    ret_val = {}
     for script in eval_xpath(dom, '//script[contains(., "_setImgSrc(")]'):
         _script = script.text
         # _setImgSrc('0','data:image\/jpeg;base64,\/9j\/4AAQSkZJR ....');