Update Wayback to v0.2.5 (#639)

This fixes a bug with fetching mementos for redirects.
Release notes: https://wayback.readthedocs.io/en/stable/release-history.html#v0-2-5-2020-10-19

Author: Mr0grog

requirements.txt

@@ -14,4 +14,4 @@ requests ~=2.24.0
 toolz ~=0.11.1
 tornado ~=6.0.4
 tqdm ~=4.50.0
-wayback ~=0.2.4
+wayback ~=0.2.5