This updates the minimal supported version of CMake to 3.16, which in turn enables us to use more CMake features and have a cleaner build system.
This is the version that provides most new features and also the one we use in our latest docker image for CI.
Fixed compile error in example. `error: designator order for field 'esp_ping_callbacks_t::cb_args' does not match declaration order in 'esp_ping_callbacks_t'`. Moved `.cb_args` in example to match declaration.
Replaced hyphens with underscores in examples
project definition for all examples which had
hyphens in their project name. dpp-enrollee is
an exceptions because the name matches the
project directory name while the project
directory also contains hyphens.
esp_netif_init() returns standard esp_err_t error code (unlike tcpip_adapter init), so shall be checked for the return value
Also to make the initialization code more consistent.
