Build project after updating to ESP-IDF 4.0

[leonardo.zambonelli]

Hi,
i've just updated to ESP-IDF 4.0. My project does not compile anymore.
This is the error:
App "SimplyConnect" version: 22ff384-dirty
WARNING: Missing submodule components/esp32/lib...
Attempting 'git submodule update --init components/esp32/lib' in esp-idf root directory...
error: pathspec 'components/esp32/lib' did not match any file(s) known to git
make[1]: *** [/esp-idf/v4.0/make/project.mk:653: /esp-idf/v4.0/components/esp32/lib/.git] Error 1
make: *** [/C/Projects/XXX/YYYY/source/fw/components/bootloader/Makefile.projbuild:41: /C/XXX/YYYY/FAAC-ftm/source/fw/build/bootloader/bootloader.bin] Error 2

Any ideas?
Thanks
Leonardo