* Correctly handle platforms that include CPU variants
Prior to this change, Kaniko would only select the platform-specific
image from a multi-platform image using the OS and architecture to
select the image. This leads to problems when there are two platforms
that are indistinguishable using only this information (e.g.,
linux/arm/v5 and linux/arm/v7).
This change more explicitly selects the right image from a
multi-platform image, taking CPU variant into account (v5 vs v7), using
containerd's CPU variant detection logic.
This also moves platform defaulting up as early as possible in execution
as it can go, so that malformed platform values are detected as soon as
possible.
* set platform in unit test
which means we can now:
- set up one or more mirrors
- set up registries certificates
- skip TLS verify
- use plain HTTP
using the same set of flags that are defined for the executor
Jason Hall
Tejal Desai
Silvano Cirujano Cuesta
Sascha Schwarze
Vincent Behar