Add python wheel egg relationships (#2903)

* add python package relationships

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

* nil for empty relationships collections

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

* new json schema for optional python requiremenets

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

* update format snapshots for python packages

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

* decompose python parsers more + add tests around plural fields

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

* update JSON schema with python dep refs

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

---------

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

syft/pkg/cataloger/lua/cataloger_test.go

@@ -1,8 +1,9 @@
 package lua
 
 import (
-	"github.com/anchore/syft/syft/pkg/cataloger/internal/pkgtest"
 	"testing"
+
+	"github.com/anchore/syft/syft/pkg/cataloger/internal/pkgtest"
 )
 
 func Test_PackageCataloger_Globs(t *testing.T) {

syft/pkg/cataloger/lua/parse_rockspec_test.go

@@ -1,10 +1,11 @@
 package lua
 
 import (
+	"testing"
+
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/pkg/cataloger/internal/pkgtest"
-	"testing"
 )
 
 func TestParseRockspec(t *testing.T) {