Fix typo in contentsecuritypolicy.ini for ObalkyKnih (vufind-org#3020)

Author: xmorave2

config/vufind/contentsecuritypolicy.ini

@@ -59,7 +59,7 @@ img-src[] = "'self'"
 ; so you should ensure they are still valid.
 ;img-src[] = https://cache.obalkyknih.cz
 ;img-src[] = https://cache2.obalkyknih.cz
-;img-src[] = https://cache2.obalkyknih.cz
+;img-src[] = https://cache3.obalkyknih.cz
 font-src[] = "'self'"
 base-uri[] = "'self'"
 ; Set URI that the browser should use to report CSP violation; you should provide