feat docs: start 2.10-rc

Tests: протестировано CI
commit_hash:b6522d4741cec23b63222cc47d22a74d3ec5deb2

Author: apolukhin

cmake/GetUserverVersion.cmake

@@ -23,7 +23,7 @@ else()
 endif()
 
 set(USERVER_MAJOR_VERSION 2)
-set(USERVER_MINOR_VERSION 9)
+set(USERVER_MINOR_VERSION 10-rc)
 
 set(USERVER_VERSION "${USERVER_MAJOR_VERSION}.${USERVER_MINOR_VERSION}")
 string(REPLACE "-" "_" USERVER_VERSION_STR "${USERVER_VERSION}")