Update cmake_minimum_version to 3.16

Follows the update to https://opensource.google/documentation/policies/cplusplus-support

Bug: crbug.com/385728496
Change-Id: Ia03250afd1b6a9c80bd282ea9172ea0f1117d097
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/220374
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef69780..0e686a5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,7 +26,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # As per https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.16)
 
 # - Since we are past CMake 3.12 we can add CONFIGURE_DEPENDS to DawnGenerator to rerun CMake
 #   in case any of the generator files changes. We should also remove the CACHE "" FORCE stuff to