vendor/dialog: upgrade from 1.3-20200327 to 1.3-20220728

vendor/dialog: upgrade from 1.3-20200327 to 1.3-20220728

Summary of notable changes:

 + initialize color-settings before --create-rc option is processed.
 + adjust fallback bindings for backspace/delete to match the curses
   library's sense of backspace (Arch #74379).
 + improve logic for updating form-height after screen-resizing.
 + correct off-by-one limit for month when validating parameters of the
   calendar widget (patch by "viverna", Debian #1000720).
 + use mktemp utility rather than tempfile for temporary filename in
   the sample scripts (patch by Ville Skyttä).
 + directly include stddef.h for systems which need it for offsetof().
 + fix a few cppcheck warnings
 + update configure macros, for quoting/escaping fixes per shellcheck
 + add option "--cursor-off-label"
 + add option "--erase-on-exit"
 + add dlg_getenv_num() and dlg_getenv_str().

For detailed list of all changes, bugfixes and improvements, see CHANGES.