Bump version to 12.0.1

Release of accumulated fixes since v12.0.0: DNS lookup crash/offline
resolution (#589), OpenSSL IP-address cert validation (#588),
case-insensitive Upgrade header (#584), server fd double-close (#585),
fragment buffering optimization (#562), and the install include-dir fix (#582).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: bsergean

CMakeLists.txt

@@ -6,7 +6,7 @@
 cmake_minimum_required(VERSION 3.4.1...3.17.2)
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/CMake;${CMAKE_MODULE_PATH}")
 
-project(ixwebsocket LANGUAGES C CXX VERSION 12.0.0)
+project(ixwebsocket LANGUAGES C CXX VERSION 12.0.1)
 
 set (CMAKE_CXX_STANDARD 11)
 set (CXX_STANDARD_REQUIRED ON)