feat(stupgrades): filter returned releases per compatibility

lib/upgrade/upgrade_common.go

@@ -27,6 +27,9 @@ type Release struct {
 	// The HTML URL is needed for human readable links in the output created
 	// by cmd/infra/stupgrades.
 	HTMLURL string `json:"html_url"`
+
+	// The compatibility information is included with each current release.
+	Compatibility *ReleaseCompatibility `json:"compatibility,omitempty"`
 }
 
 type Asset struct {
@@ -39,7 +42,7 @@ type Asset struct {
 }
 
 // ReleaseCompatibility defines the structure of compat.json, which is
-// included with each elease.
+// included with each release.
 type ReleaseCompatibility struct {
 	Runtime      string            `json:"runtime,omitempty"`
 	Requirements map[string]string `json:"requirements,omitempty"`