There are builds which rely on having the numeric version of gcc (eg "10.2.1")
declared in an environment variable.
Running 'arm-none-eabi-gcc --version' returns:
"arm-none-eabi-gcc (GNU Arm Embedded Toolchain 10-2020-q4-major) 10.2.1 20201103 (release)"
However, the attribute arm-none-eabi-gcc.version is "10-2020-q4-major",
from which there is no way to derive "10.2.1".
Contrast this with the attribute gcc.version which (at this time) gives "10.3.0".
By adding a numVersion attribute, consumers of this package can
correctly determine what GCC version is being executed.
Signed-off-by: Sirio Balmelli <sirio@b-ad.ch>
