fix(2.2 json): remove emtpy packageVerificationCode

Signed-off-by: Keith Zantow <kzantow@gmail.com>

spdx/v2/v2_2/package.go

@@ -4,6 +4,7 @@ package v2_2
 
 import (
 	"encoding/json"
+	"regexp"
 	"strings"
 
 	"github.com/spdx/tools-golang/spdx/v2/common"
@@ -122,6 +123,20 @@ type Package struct {
 	hasFiles []common.DocElementID
 }
 
+var emptyVerificationCodeRegex = regexp.MustCompile(`,\s*"packageVerificationCode"\s*:\s*\{\s*"packageVerificationCodeValue"\s*:\s*""\s*}`)
+
+func (p *Package) MarshalJSON() ([]byte, error) {
+	type pkg Package
+	p2 := pkg(*p)
+
+	data, err := json.Marshal(p2)
+	if err != nil {
+		return nil, err
+	}
+
+	return emptyVerificationCodeRegex.ReplaceAll(data, []byte("")), nil
+}
+
 func (p *Package) UnmarshalJSON(b []byte) error {
 	type pkg Package
 	type extras struct {
@@ -153,6 +168,7 @@ func (p *Package) UnmarshalJSON(b []byte) error {
 }
 
 var _ json.Unmarshaler = (*Package)(nil)
+var _ json.Marshaler = (*Package)(nil)
 
 // PackageExternalReference is an External Reference to additional info
 // about a Package, as defined in section 7.21 in version 2.2 of the spec.