Raise cmake_minimum_required to VERSION 3.16 in examples

Pick-to: 6.2
Task-number: QTBUG-95636
Change-Id: Iaded00e0fd274a27aeefb26d8211ce546d278399
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

examples/virtualkeyboard/basic/CMakeLists.txt

 # Generated from basic.pro.
 
-cmake_minimum_required(VERSION 3.14)
+cmake_minimum_required(VERSION 3.16)
 project(basic LANGUAGES CXX)
 
 set(CMAKE_INCLUDE_CURRENT_DIR ON)