migrate to track2 azure go sdk

[HuShaoRu]

Migrate to the latest version of Azure SDK for Go (known as track2), as old version of Azure SDK for go (known as track1) is deprecated and no longer recieving support.

as resource sku definitions in track1 and track2 are different, I made some necessary breaking changes:

• use armcompute.ResourceSKUsClient instead of compute.ResourceSkusClient, in interface.go, client.go, cache.go
• use armcompute.ResourceSKU instead of compute.ResourceSku, in sku.go, wrap.go
  as track2 List returns []* instead of [], and some properties use []* instead of *[], I changed some usages (for example, nil check) of those models.
  I don't change SKU here, so SKU is not pointer and data is still []SKU but not []*armcompute.ResourceSKU, which might be different from sdk pattern.
• bump package version from github.com/Azure/skewer to github.com/Azure/skewer/v2, in go.mod
  it's useless and not easy to keep both v1 and v2 version here, so I would like to migrate the whole package to v2. (maybe we can use another branch but use v2 tag, then we can use both v1 or v2 skewer)

[HuShaoRu]

I can't run golangci-lint run --fix, may because the version and configurations are so old. Only run other checks.

[HuShaoRu]

2 questions:

1. should we merge to main? we can also create another branch named dev or v2 or track2 , just need to tag it . (in pull request I can only merge into an existing branch)
2. should SKU be armcompute.ResourceSKU or *armcompute.ResourceSKU? in track2 sdk, the items in [] are always poiners