third_party: update nghttp2 from 1.47.0 to 1.48.0

This is just regular update to bring bugfixes and improvements in the
library into tarantool.

https://github.com/nghttp2/nghttp2/releases/tag/v1.48.0

NO_DOC=there is no known behavior changes, consider the change as not
       visible for a user
NO_TEST=there is no specific problem we want to solve and verify here
NO_CHANGELOG=see NO_DOC