fix urqmd warnings

Processes/UrQMD/testUrQMD.cc

@@ -140,6 +140,7 @@ TEST_CASE("UrQMD") {
 
   SECTION("cross sections") {
     auto [env, csPtr, nodePtr] = setupEnvironment(particles::Code::Unknown);
+    [[maybe_unused]] const auto& env_dum = env;
     auto const& cs = *csPtr;
 
     particles::Code validProjectileCodes[] = {
@@ -169,9 +170,11 @@ TEST_CASE("UrQMD") {
 
   SECTION("nucleon projectile") {
     auto [env, csPtr, nodePtr] = setupEnvironment(particles::Code::Oxygen);
+    [[maybe_unused]] const auto& env_dum = env;
     unsigned short constexpr A = 14, Z = 7;
     auto [stackPtr, secViewPtr] = setupStack(A, Z, 400_GeV, nodePtr, *csPtr);
-
+    [[maybe_unused]] const auto& stackPtr_dump = stackPtr;
+      
     // must be assigned to variable, cannot be used as rvalue?!
     auto projectile = secViewPtr->GetProjectile();
     auto const projectileMomentum = projectile.GetMomentum();
@@ -188,8 +191,10 @@ TEST_CASE("UrQMD") {
 
   SECTION("\"special\" projectile") {
     auto [env, csPtr, nodePtr] = setupEnvironment(particles::Code::Oxygen);
+    [[maybe_unused]] const auto& env_dum = env;
     auto [stackPtr, secViewPtr] =
         setupStack(particles::Code::PiPlus, 400_GeV, nodePtr, *csPtr);
+    [[maybe_unused]] const auto& stackPtr_dump = stackPtr;
 
     // must be assigned to variable, cannot be used as rvalue?!
     auto projectile = secViewPtr->GetProjectile();