Add test to ensure package metadata is represented in the JSON schema (#1841)

* [wip] try to reflect metadata types... probably wont work

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* refactor to add unit test to ensure there is coverage in the schema

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* [wip] generate metadata container

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add generation of metadata container struct for JSON schema generation

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* fix linting

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* update linter script to account for code generation

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

---------

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

schema/json/generate/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/dave/jennifer/jen"
+
+	"github.com/anchore/syft/schema/json/internal"
+)
+
+// This program generates internal/generated.go.
+
+const (
+	pkgImport = "github.com/anchore/syft/syft/pkg"
+	path      = "internal/generated.go"
+)
+
+func main() {
+	typeNames, err := internal.AllSyftMetadataTypeNames()
+	if err != nil {
+		panic(fmt.Errorf("unable to get all metadata type names: %w", err))
+	}
+
+	fmt.Printf("updating metadata container object with %+v types\n", len(typeNames))
+
+	f := jen.NewFile("internal")
+	f.HeaderComment("DO NOT EDIT: generated by schema/json/generate/main.go")
+	f.ImportName(pkgImport, "pkg")
+	f.Comment("ArtifactMetadataContainer is a struct that contains all the metadata types for a package, as represented in the pkg.Package.Metadata field.")
+	f.Type().Id("ArtifactMetadataContainer").StructFunc(func(g *jen.Group) {
+		for _, typeName := range typeNames {
+			g.Id(typeName).Qual(pkgImport, typeName)
+		}
+	})
+
+	rendered := fmt.Sprintf("%#v", f)
+
+	fh, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		panic(fmt.Errorf("unable to open file: %w", err))
+	}
+	_, err = fh.WriteString(rendered)
+	if err != nil {
+		panic(fmt.Errorf("unable to write file: %w", err))
+	}
+	if err := fh.Close(); err != nil {
+		panic(fmt.Errorf("unable to close file: %w", err))
+	}
+}