Resolves #510

---------

Signed-off-by: Billy Zha <jinzha1@microsoft.com>

https://github.com/opencontainers/image-spec/blob/v1.0/image-layout.md#content
specifies that the blobs dir must exist, so the changed ensureDir in
this PR is a bugfix.

The addition and use of the ociBlobsDir constant is more of a cleanup
suggestion, and I can remove it if necessary. I've also asked for it to
be added upstream at
opencontainers/image-spec#1069 but that will
probably take significantly longer.

Signed-off-by: Clarence "Sparr" Risher <clrnc@amazon.com>

NewWithContext refers to both the `oci-layout` and `index.json` as "OCI
Image Layout", this PR fixes the latter.

ReadAll is a deeper change that will improve error reporting for a lot
of cases, at the cost of error volume. Some or all of that change could
happen higher up to satisfy this particular issue. I think the
expected/actual size output belongs here. There seem to be more than a
few code paths in this and other repos that end up calling ReadAll
multiple times without reporting which call produced an error so I think
it's appropriate to also output the digest here, but that's less
compelling.

The Verify comment clears up confusion I encountered while working on
this issue. "verifies size" implies checking for both too big AND too
small, but it only checks if the file is bigger (or reader is longer)
than expected.

Fixes #432

Signed-off-by: Clarence "Sparr" Risher <clrnc@amazon.com>

…ng types (#536)

Resolves: #530

Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Resolves: #531
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

…m to image-spec v1.1.0-rc4 (#550)

1. Introduce `PackOptions.PackManifestType`
2. Introduce `DefaultPackOptions`

Resolves: #532
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Resolves: #443
Resolves: #533
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

…spec v1.1.0-rc3 (#557)

1. Support pushing image index with a subject
2. Check the "OCI-Subject" header

Resolves: #534
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

…-spec v1.1.0-rc3 (#558)

Support deleting image indexes with a subject

Resolves: #535
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Resolves: #554
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Add `Repository.HandleWarning(Warning)` that handles encountered warning
headers.

Resolves: #469
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Resolves #434 
Signed-off-by: Xiaoxuan Wang <wangxiaoxuan119@gmail.com>

Following up issue #434 
Signed-off-by: Xiaoxuan Wang <xiaoxuanwang@microsoft.com>

Related issue: #532 
Related discussion:
oras-project/oras#1011 (comment)

Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

This PR refactors `oras.Pack` that was updated by #532.

1. Move the support of Image Manifest `v1.1.0-rc4` to `PackManifest`
2. Deprecate `Pack`

Resolves: #568
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>

Resolves: #571
Signed-off-by: Lixia (Sylvia) Lei <lixlei@microsoft.com>