cmake: Set minimum required Zephyr SDK version to 0.13

In order to use the newlib retagetable locking interface (for thread
safety), which requires the newlib multi-threading feature to be
enabled, the Zephyr SDK 0.13.0 or above must be used.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
1 file changed