main/xen: add missing CVE info

CVEs now assigned.

main/xen/APKBUILD

@@ -188,14 +188,14 @@ options="!strip"
 #     - CVE-2020-25599 XSA-343
 #     - CVE-2020-25601 XSA-344
 #   4.13.2-r0:
-#     - CVE-????-????? XSA-286
-#     - CVE-????-????? XSA-345
-#     - CVE-????-????? XSA-346
-#     - CVE-????-????? XSA-347
+#     - CVE-2020-27674 XSA-286
+#     - CVE-2020-27672 XSA-345
+#     - CVE-2020-27671 XSA-346
+#     - CVE-2020-27670 XSA-347
 #   4.13.2-r1:
 #     - CVE-2020-28368 XSA-351
 #   4.13.2-r2:
-#     - CVE-????-????? XSA-355
+#     - CVE-2020-29040 XSA-355
 #   4.13.2-r3:
 #     - CVE-2020-29480 XSA-115
 #     - CVE-2020-29481 XSA-322