Prevents helmfile from consuming unnecessarily much time in running `helm repo update` over and over.
helmfile now marks which repository was updated, and skip second and further `helm repo update` when all the `repositories` found in a helmfile.yaml was marked as already updated.
Let's say you had two helmfiles, the first one with repositories `foo` and `bar`, an the second one with only `bar`. `helmfile repos` will run `helm update repo` for the first helmfile, marking `foo` and `bar` as already updated. The second helmfile.yaml contains only `bar`, which is marked as already updated. So helmfile won't run `helm repo update` for the second.
This applies to all the helmfile command that results in `helm repo update`, like `repos`, `sync`, `diff` and so on.
Resolves#335
b94265122f