fix : forgot to invert condition in if=>assert refactor

src/operator/GlobalAveragePooling.cpp

@@ -28,8 +28,8 @@ void Aidge::GlobalAveragePooling_Op::computeOutputDims() {
     return;
   // computation
   } else {
-    AIDGE_ASSERT(getInput(0)->dims().size() < 3,
-                 "GlobalAveragePooling :  needs at least 3 dimensions input, "
+    AIDGE_ASSERT(getInput(0)->dims().size() >= 3,
+                 "GlobalAveragePooling :  needs at least a 3 dimensions input, "
                  "number of input dim : {}",
                  getInput(0)->dims().size());
     // Global average pooling takes each filter, averages its values and uses