testbed: updated refs

testbed/CMakeLists.txt

@@ -7,7 +7,7 @@ include(FetchContent)
 FetchContent_Declare(
     SDL3
     GIT_REPOSITORY https://github.com/libsdl-org/SDL
-    GIT_TAG release-3.2.10
+    GIT_TAG release-3.4.12
     GIT_SHALLOW 1
 )
 
@@ -21,7 +21,7 @@ FetchContent_MakeAvailable(SDL3)
 FetchContent_Declare(
     imgui
     GIT_REPOSITORY https://github.com/ocornut/imgui
-    GIT_TAG v1.91.9
+    GIT_TAG v1.92.8
     GIT_SHALLOW 1
 )