Add LOG_COMPRESSION (#50)

Follow https://github.com/go-gitea/gitea/pull/31761

Reviewed-on: https://gitea.com/gitea/docs/pulls/50
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Jason Song <i@wolfogre.com>
Co-committed-by: Jason Song <i@wolfogre.com>

docs/administration/config-cheat-sheet.md

@@ -1459,6 +1459,11 @@ PROXY_HOSTS = *.github.com
 - `STORAGE_TYPE`: **local**: Storage type for actions logs, `local` for local disk or `minio` for s3 compatible object storage service, default is `local` or other name defined with `[storage.xxx]`
 - `MINIO_BASE_PATH`: **actions_log/**: Minio base path on the bucket only available when STORAGE_TYPE is `minio`
 - `LOG_RETENTION_DAYS`: **365**: Logs retention time in days. Old logs will be deleted after this period.
+- `LOG_COMPRESSION`: **none**: Log compression type, `none` for no compression, `zstd` for zstd compression.
+  Other compression types like `gzip` are NOT supported, since seekable stream is required for log view.
+  It's always recommended to use compression when using local disk as log storage if CPU or memory is not a bottleneck.
+  And for object storage services like S3, which is billed for requests, it would cause extra 2 times of get requests for each log view.
+  But it will save storage space and network bandwidth, so it's still recommended to use compression.
 - `ARTIFACT_RETENTION_DAYS`: **90**: Default number of days to keep artifacts. Artifacts could have their own retention periods by setting the `retention-days` option in `actions/upload-artifact` step.
 - `ZOMBIE_TASK_TIMEOUT`: **10m**: Timeout to stop the task which have running status, but haven't been updated for a long time
 - `ENDLESS_TASK_TIMEOUT`: **3h**: Timeout to stop the tasks which have running status and continuous updates, but don't end for a long time