change robdekon gcc version back to 8

data/modules/h2t/research_projects/robdekon/robdekon.json

@@ -13,8 +13,8 @@
     "cmake": {
       "project_name": "robdekon",
       "definitions": {
-        "CMAKE_C_COMPILER": "$GCC_9",
-        "CMAKE_CXX_COMPILER": "$GXX_9",
+        "CMAKE_C_COMPILER": "$GCC_8",
+        "CMAKE_CXX_COMPILER": "$GXX_8",
         "CMAKE_BUILD_TYPE": "Debug"
       }
     }
@@ -26,7 +26,7 @@
     }
   },
   "required_modules": {
-    "apt/gxx-9": {},
+    "apt/gxx-8": {},
     "apt/libglew-dev": {},
 
     "armarx/ArmarXCore": {},