schema: Add entry for baseos-container

For now, we need to support having the new format oscontainer in
`meta.json`.

Part of coreos#2685
And see coreos#2685 (comment)
in particular.

Author: cgwalters

gangplank/vendor/github.com/coreos/coreos-assembler-schema/cosa/cosa_v1.go

@@ -1,7 +1,7 @@
 package cosa
 
 // generated by 'make schema'
-// source hash: be093d10a3ebf57e28907a5676a88928631bb09eee602dff89f381ddd1ca8f5e
+// source hash: ec49fcff4b25566b5f515909fd5fcc22a51c169449e8a6f50390551f7bf97506
 
 type AdvisoryDiff []AdvisoryDiffItems
 
@@ -27,13 +27,18 @@ type Artifact struct {
 	UncompressedSize   int     `json:"uncompressed-size,omitempty"`
 }
 
+type BaseOsContainer struct {
+	Image string `json:"image"`
+}
+
 type Build struct {
 	AdvisoryDiffAgainstParent AdvisoryDiff          `json:"parent-advisories-diff,omitempty"`
 	AdvisoryDiffBetweenBuilds AdvisoryDiff          `json:"advisories-diff,omitempty"`
 	AlibabaAliyunUploads      []AliyunImage         `json:"aliyun,omitempty"`
 	Amis                      []Amis                `json:"amis,omitempty"`
 	Architecture              string                `json:"coreos-assembler.basearch,omitempty"`
 	Azure                     *Cloudartifact        `json:"azure,omitempty"`
+	BaseOsContainer           *BaseOsContainer      `json:"base-oscontainer,omitempty"`
 	BuildArtifacts            *BuildArtifacts       `json:"images,omitempty"`
 	BuildID                   string                `json:"buildid"`
 	BuildRef                  string                `json:"ref,omitempty"`

gangplank/vendor/github.com/coreos/coreos-assembler-schema/cosa/schema_doc.go

@@ -1,5 +1,5 @@
 // Generated by ./generate-schema.sh
-// Source hash: be093d10a3ebf57e28907a5676a88928631bb09eee602dff89f381ddd1ca8f5e
+// Source hash: ec49fcff4b25566b5f515909fd5fcc22a51c169449e8a6f50390551f7bf97506
 // DO NOT EDIT
 
 package cosa
@@ -211,6 +211,7 @@ var generatedSchemaJSON = `{
    "amis",
    "azure",
    "azurestack",
+   "base-oscontainer",
    "build-url",
    "digitalocean",
    "exoscale",
@@ -842,6 +843,21 @@ var generatedSchemaJSON = `{
      "title":"Azure",
      "$ref": "#/definitions/cloudartifact"
     },
+    "base-oscontainer": {
+      "$id":"#/properties/base-oscontainer",
+      "type":"object",
+      "title":"Base OS container",
+      "required": [
+        "image"
+      ],
+      "properties": {
+        "image": {
+          "$id":"#/properties/base-oscontainer/image",
+          "type":"string",
+          "title":"Image"
+        }
+      }
+    },
    "gcp": {
      "$id":"#/properties/gcp",
      "type":"object",

mantle/vendor/github.com/coreos/coreos-assembler-schema/cosa/cosa_v1.go

@@ -205,6 +205,7 @@
    "amis",
    "azure",
    "azurestack",
+   "base-oscontainer",
    "build-url",
    "digitalocean",
    "exoscale",
@@ -836,6 +837,21 @@
      "title":"Azure",
      "$ref": "#/definitions/cloudartifact"
     },
+    "base-oscontainer": {
+      "$id":"#/properties/base-oscontainer",
+      "type":"object",
+      "title":"Base OS container",
+      "required": [
+        "image"
+      ],
+      "properties": {
+        "image": {
+          "$id":"#/properties/base-oscontainer/image",
+          "type":"string",
+          "title":"Image"
+        }
+      }
+    },
    "gcp": {
      "$id":"#/properties/gcp",
      "type":"object",

mantle/vendor/github.com/coreos/coreos-assembler-schema/cosa/schema_doc.go

@@ -205,6 +205,7 @@
    "amis",
    "azure",
    "azurestack",
+   "base-oscontainer",
    "build-url",
    "digitalocean",
    "exoscale",
@@ -836,6 +837,21 @@
      "title":"Azure",
      "$ref": "#/definitions/cloudartifact"
     },
+    "base-oscontainer": {
+      "$id":"#/properties/base-oscontainer",
+      "type":"object",
+      "title":"Base OS container",
+      "required": [
+        "image"
+      ],
+      "properties": {
+        "image": {
+          "$id":"#/properties/base-oscontainer/image",
+          "type":"string",
+          "title":"Image"
+        }
+      }
+    },
    "gcp": {
      "$id":"#/properties/gcp",
      "type":"object",