fix: update steroscope to include OCI platform metadata (#5128)

* Update steroscope to include OCI platform metadata

Signed-off-by: Jason Paulos <jasonpaulos@users.noreply.github.com>

* chore(deps): point stereoscope at anchore/main

drops the fork `replace` directive and moves to a pseudo-version off stereoscope
main (`a22e5ae`, anchore/stereoscope#657). no tag carries it yet, so this should
move to a real version once one is cut.

`readImageMetadata` now fills os/architecture/variant for every provider, not
just oci. the docker tarball provider set neither before, so image metadata and
the image purl change for docker-archive input too:

- `"architecture": ""` -> `"amd64"`
- `"os": ""` -> `"linux"`
- `?arch=` -> `?arch=amd64`

the empty `arch=` qualifier was never right, but it is user-visible output.

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* test: cover single-platform oci layouts

the pr only added assertions to the multiplatform fixture, which already
reported the right platform. the behavior that actually changed is single-image
layouts: they used to report empty os/arch and silently ignore `--platform`, and
now report what the image config says and fail with a platform mismatch.

also drops the non-linux skip on the default-platform test. the oci providers
default to `linux/<GOARCH>` regardless of host os, so it holds on macos too.

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Jason Paulos <jasonpaulos@users.noreply.github.com>
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Co-authored-by: Alex Goodman <wagoodman@users.noreply.github.com>

syft/format/spdxjson/testdata/snapshot/TestSPDXJSONImageEncoder.golden

@@ -81,7 +81,7 @@
     {
      "referenceCategory": "PACKAGE-MANAGER",
      "referenceType": "purl",
-     "referenceLocator": "pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch="
+     "referenceLocator": "pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=amd64"
     }
    ],
    "primaryPackagePurpose": "CONTAINER"

syft/format/spdxjson/testdata/snapshot/TestSPDXRelationshipOrder.golden

@@ -81,7 +81,7 @@
     {
      "referenceCategory": "PACKAGE-MANAGER",
      "referenceType": "purl",
-     "referenceLocator": "pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch="
+     "referenceLocator": "pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=amd64"
     }
    ],
    "primaryPackagePurpose": "CONTAINER"

syft/format/spdxtagvalue/testdata/snapshot/TestSPDXRelationshipOrder.golden

@@ -71,7 +71,7 @@ PackageChecksum: SHA256: 2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf4
 PackageLicenseConcluded: NOASSERTION
 PackageLicenseDeclared: NOASSERTION
 PackageCopyrightText: NOASSERTION
-ExternalRef: PACKAGE-MANAGER purl pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=
+ExternalRef: PACKAGE-MANAGER purl pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=amd64
 
 ##### Package: package-2
 

syft/format/spdxtagvalue/testdata/snapshot/TestSPDXTagValueImageEncoder.golden

@@ -21,7 +21,7 @@ PackageChecksum: SHA256: 2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf4
 PackageLicenseConcluded: NOASSERTION
 PackageLicenseDeclared: NOASSERTION
 PackageCopyrightText: NOASSERTION
-ExternalRef: PACKAGE-MANAGER purl pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=
+ExternalRef: PACKAGE-MANAGER purl pkg:oci/user-image-input@sha256%3A2731251dc34951c0e50fcc643b4c5f74922dad1a5d98f302b504cf46cd5d9368?arch=amd64
 
 ##### Package: package-2
 

syft/format/syftjson/testdata/snapshot/TestImageEncoder.golden

@@ -105,8 +105,8 @@
    "manifest": "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",
    "config": "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",
    "repoDigests": [],
-   "architecture": "",
-   "os": ""
+   "architecture": "amd64",
+   "os": "linux"
   }
  },
  "distro": {