doc: remove outdated warning

README.md

@@ -9,23 +9,6 @@
 log4rs is a highly configurable logging framework modeled after Java's Logback
 and log4j libraries.
 
-## Warning
-
-If you are using the file rotation in your configuration there is a known
-substantial performance issue so listen up! By default the `gzip` feature
-is enabled and when rolling files it will zip log archives automatically.
-This is a problem when the log archives are large as the zip happens in the
-main thread and will halt the process while the zip is completed. Be advised
-that the `gzip` feature will be removed from default features as of `1.0`.
-
-The methods to mitigate this are as follows.
-
-1. Use the `background_rotation` feature which spawns an os thread to do the compression.
-1. Disable the `gzip` feature with `--no-default-features`.
-1. Ensure the archives are small enough that the compression time is acceptable.
-
-For more information see the PR that added [`background_rotation`](https://github.com/estk/log4rs/pull/117).
-
 ## Quick Start
 
 log4rs.yaml: