quote field because validator doesn't like it unquoted

cpansa/CPANSA-Net-Dropbear.yml

@@ -8,7 +8,7 @@ advisories:
   description: |
     In LibTomCrypt through 1.18.2, the der_decode_utf8_string function (in der_decode_utf8_string.c) does not properly detect certain invalid UTF-8 sequences. This allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) or read information from other memory locations via carefully crafted DER-encoded data.
   embedded_vulnerability:
-    affected_versions: <0
+    affected_versions: '<0'
     distributed_version: 1.8.2
     name: libtomcrypt
   fixed_versions: '>0'