For the PATCH value of the VERSION variable the git sha of the last
commit was used, but in case of a release we want to change that value
to 0, so it can be added in a package repository.

If we set an environment variable IS_RELEASE then the PATCH variable will
remain 0, otherwise will still be initialized with git sha.

Signed-off-by: Andreea Andrisan <Andreea.Andrisan@analog.com>

After switching to patch variable artifact check also needs to be
updated.

Signed-off-by: Andreea Andrisan <Andreea.Andrisan@analog.com>

In order to extract the git sha of the last commit from libiio the
directory where a volume of the project was created needs to be set as
safe, otherwise an error message will appear.

Signed-off-by: Andreea Andrisan <Andreea.Andrisan@analog.com>

In order to maintain the same length of the git sha during package
creation all the jobs must have the same parameters at repository checkout.

Signed-off-by: Andreea Andrisan <Andreea.Andrisan@analog.com>

In case the build was triggered for a release purpose we don't want to
use the git sha in the version of libiio.

The new variable will be used in order to identify that is a build
dedicated to a release.

Signed-off-by: Andreea Andrisan <Andreea.Andrisan@analog.com>