Update minimum_cmake_required to match version used in CI (#679)

- Update minimum_cmake_required to match version used in CI
  - We should match the minimum version that we test against

- Ensure ".S" files are treated as assembly.

projects/rocprofiler-systems/examples/code-coverage/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.18.4 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.21 FATAL_ERROR)
 
 project(rocprofiler-systems-code-coverage-example LANGUAGES CXX)