chore: update eredis to 1.3.0

[hjianbo]

Summary

• Bumps eredis_cluster to 0.9.0.
• Updates eredis from 1.2.18 to the released 1.3.0 tag.
• Picks up Redis Sentinel manager isolation from fix: isolate Redis Sentinel managers eredis#31 while keeping eredis_cluster code unchanged because it only consumes eredis through direct Redis connections.
• Uses a minor version bump because eredis 1.3.0 adds a new transitive OTP application dependency (gproc) and changes the Redis Sentinel integration surface.
• Local checks: make all, Docker-backed rebar3 eunit -v -c, and rebar3 cover -v.