feat: bump go-redis from v8 to v9

[cwp0]

Fix: #42

[casbin-bot]

@tangyang9464 @JalinWang @imp2002 please review

[CLAassistant]

All committers have signed the CLA.

[sixcolors]

Hi, I just wanted to bring to your attention that this pull request appears to be a copy of my open pull request #43. Just using an unreleased v9 commit. While I appreciate the effort to contribute to the project, I would appreciate it if proper credit was given for my original work. Thank you.

[hsluoyz]

@sixcolors hi, is it acceptable to let the PR contain your original commit (with your original author info) including other new commits? Or do you think the PR should be discarded totally? If the latter is your choice, we will revert all related PRs for now.

[sixcolors]

@sixcolors hi, is it acceptable to let the PR contain your original commit (with your original author info) including other new commits? Or do you think the PR should be discarded totally? If the latter is your choice, we will revert all related PRs for now.

@hsluoyz either option is acceptable, thank you.

#43 was left open in hope that go-redis would add a tagged release. Because go mod tidy will always update to the highest semantic release of a direct dependency. Thus other projects using redis-watcher would then also be updated to a non release commit of go-redis.