fix cmake list (#582)

The CMake list for extern/actsvg missed the actsvg::web module to be built.

extern/actsvg/CMakeLists.txt

@@ -1,6 +1,6 @@
 # Detray library, part of the ACTS project (R&D line)
 #
-# (c) 2021-2022 CERN for the benefit of the ACTS project
+# (c) 2021-2023 CERN for the benefit of the ACTS project
 #
 # Mozilla Public License Version 2.0
 
@@ -25,5 +25,8 @@ FetchContent_Declare( actsvg
    GIT_REPOSITORY "${DETRAY_ACTSVG_GIT_REPOSITORY}"
    GIT_TAG "${DETRAY_ACTSVG_GIT_TAG}" )
 
+# Make sure the web plugin of ACTSVG is built
+set(ACTSVG_BUILD_WEB ON CACHE BOOL "Build the web plugin of ACTSVG")
+
 # Now set up its build.
 FetchContent_MakeAvailable( actsvg )