Vagrant: support Mbed CLI 2

To use Mbed CLI 2, the python package `mbed-tools` is required, and
the version of CMake needs to be at least 3.19 so we fetch the latest
from the offical PPA.

Author: LDong-Arm

vagrant/bootstrap-user.sh

@@ -7,4 +7,4 @@ mkdir -p ~/.local
 mv gcc-arm-none-eabi-9-2019-q4-major/* ~/.local/
 
 # Python environment
-python3 -m pip install --user cryptography pyasn1 pyyaml jinja2 cbor mbed-cli
+python3 -m pip install --user cryptography pyasn1 pyyaml jinja2 cbor mbed-cli mbed-tools

vagrant/bootstrap.sh

@@ -1,5 +1,8 @@
 #!/usr/bin/env bash
 
+wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | \
+        gpg --dearmor - | sudo tee /etc/apt/trusted.gpg.d/kitware.gpg >/dev/null
+apt-add-repository -y 'deb https://apt.kitware.com/ubuntu/ focal main'
 apt-get update
 apt-get full-upgrade -y
 apt-get install -y \