message: fix: UnitTestLogger -> SimpleLogger
diff: #include <iostream>
  #include <unordered_map>
  #include "CLI11/CLI11.hpp"
  -#include "axom/slic/core/UnitTestLogger.hpp"
  +#include "axom/slic/core/SimpleLogger.hpp"
  #include "mfem.hpp"
  using axom::inlet::FunctionType;
  @@ -159,7 +159,7 @@ int main(int argc, char** argv)
  {
  #ifdef MFEM_STDFUNCTION_COEF
  // Inlet requires a SLIC logger to be initialized to output runtime information
  - axom::slic::UnitTestLogger logger;
  + axom::slic::SimpleLogger logger;
  CLI::App app {"Example of Axom's Inlet component with user-defined types"};
  // Intended to be used with mfem_coef.lua
  