new warnings with CMake 3.31

[BenWibking]

When configuring a Parthenon build with CMake 3.31.0, these warnings appear:

CMake Warning (dev) at cmake/CodeCov.cmake:132 (add_custom_command):
  Exactly one of PRE_BUILD, PRE_LINK, or POST_BUILD must be given.  Assuming
  POST_BUILD to preserve backward compatibility.

  Policy CMP0175 is not set: add_custom_command() rejects invalid arguments.
  Run "cmake --help-policy CMP0175" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.
Call Stack (most recent call first):
  CMakeLists.txt:402 (create_pathenon_coverage_targets)
This warning is for project developers.  Use -Wno-dev to suppress it.

and in external/Catch2:

CMake Deprecation Warning at external/Catch2/CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.10 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.