feat docs: release 2.6

Tests: протестировано CI
commit_hash:1eb47626f57ccf2624cf092b89df9f97764f0e60

Author: apolukhin

cmake/GetUserverVersion.cmake

@@ -23,7 +23,7 @@ else()
 endif()
 
 set(USERVER_MAJOR_VERSION 2)
-set(USERVER_MINOR_VERSION 6-rc)
+set(USERVER_MINOR_VERSION 6)
 
 set(USERVER_VERSION "${USERVER_MAJOR_VERSION}.${USERVER_MINOR_VERSION}")
 string(REPLACE "-" "_" USERVER_VERSION_STR "${USERVER_VERSION}")