Update minimum cmake version to 3.5

Currently, cmake is emitting the following warning:

```
CMake Deprecation Warning at cmake/ccache.cmake:23 (cmake_minimum_required):
  Compatibility with CMake < 3.5 will be removed from a future version of
  CMake.
```

Update the CMake min version to 3.5 to unclutter the build logs and ensure users don't get broken by the deprecation.

test/CMakeLists.txt

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.5)
 
 add_subdirectory(unit_test/runtime)
 add_subdirectory(unit_test/static)

test/unit_test/runtime/CMakeLists.txt

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.5)
 
 find_package(Catch2 3 CONFIG REQUIRED)
 

test/unit_test/static/CMakeLists.txt

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.5)
 
 add_library(unit_tests_static_truncating quantity_test.cpp)
 target_link_libraries(unit_tests_static_truncating PRIVATE mp-units::mp-units)