[R-package] [docs] update cran-comments for v4.5.0 release

[jameslamb]

v4.5.0 has been accepted to CRAN and is passing almost all checks (one has not been run yet).

ref: https://cran.r-project.org/web/checks/check_results_lightgbm.html

This proposes updating cran-comments.md to indicate that this release was accepted to CRAN.

[StrikerRUS]

(one has not been run yet).

Actually two right now:

[StrikerRUS]

Hope additional checks will be OK as well. 🤞

[jameslamb]

Actually two right now

Ah yes, you're right. Looks like *-debian-clang was run (successfully) very recently, so NOW there is only 1 left. And I guess any of the "Additional Checks" (https://cran.r-project.org/web/checks/check_issue_kinds.html), whose logs and status are hidden and only reported when they show a problem.