Require Boost.Fiber

As of Boost 1.87, boost::asio::spawn() uses Fiber, not Coroutine v1.
boostorg/asio@df973a85ed69f021

CMakeLists.txt

@@ -173,7 +173,7 @@ else()
   set(LOGROTATE_CREATE "\n\tcreate 644 ${ICINGA2_USER} ${ICINGA2_GROUP}")
 endif()
 
-find_package(Boost ${BOOST_MIN_VERSION} COMPONENTS coroutine context date_time filesystem iostreams thread system program_options regex REQUIRED)
+find_package(Boost ${BOOST_MIN_VERSION} COMPONENTS coroutine context date_time fiber filesystem iostreams thread system program_options regex REQUIRED)
 
 # Boost.Coroutine2 (the successor of Boost.Coroutine)
 # (1) doesn't even exist in old Boost versions and