docs: update CHANGELOG for v3.0.8 release

Author: dvershinin

CHANGELOG.md

@@ -2,6 +2,28 @@
 
 All notable changes to this project will be documented in this file.
 
+## [3.0.8] - 2025-12-07
+
+### Fixed
+- Docker startup failure when `SECRET` not provided ([#21](https://github.com/GetPageSpeed/MTProxy/issues/21)):
+  - Added `vim-common` package to provide `xxd` for automatic secret generation
+  - Secret is now auto-generated if not provided via environment variable
+- Container "cannot raise open file limit" error:
+  - Added `-c` flag with `MAX_CONNECTIONS` env var (default: 60000)
+  - Added `ulimits` configuration to docker-compose files
+
+### Added
+- CI testing workflow with GitHub Actions
+- Simplified test suite (HTTP stats + MTProto port connectivity)
+- `TESTING.md` documentation
+- Docker Quick Start section in README - run with zero configuration
+- `EXTERNAL_IP` environment variable for NAT support in Docker
+- Explicit `--platform linux/amd64` in Dockerfile for Apple Silicon compatibility
+
+### Changed
+- Simplified test suite - removed Telethon dependency for faster, more reliable CI
+- Updated Docker documentation with clearer examples
+
 ## 2025-11-28
 
 - Fixed high CPU usage (Issue #100):