vendor: move vendored sources in-tree

This should make it easier to see changes instead of just a blob

vendor/github.com/go-openapi/spec/url_go19.go

@@ -0,0 +1,11 @@
+package spec
+
+import "net/url"
+
+func parseURL(s string) (*url.URL, error) {
+	u, err := url.Parse(s)
+	if err == nil {
+		u.OmitHost = false
+	}
+	return u, err
+}