crun: switch to main as specified branch
crun: switch to main as specified branch

The upstream project has moved from master to main, so we adjust
our recipe accordingly.

Signed-off-by: Bruce Ashfield <284cc737d174a260eec2a2a6324a304f84b1ae0f@gmail.com>

lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization