bump base for MuPDF 1.13.0 (#3927)
bump base for MuPDF 1.13.0 (#3927)

https://github.com/koreader/koreader-base/pull/660
Frenzie/koreader,koreader/koreader,houqp/koreader,lgeek/koreader,mihailim/koreader,mwoz123/koreader,NiLuJe/koreader,Markismus/koreader,Frenzie/koreader,koreader/koreader,Hzj-jie/koreader,poire-z/koreader,poire-z/koreader,NiLuJe/koreader,pazos/koreader