fix: Handle CNAMEs with a trailing dot

internal/dns/dns.go

@@ -61,10 +61,13 @@ func LookupCNAME(domain string) (string, error) {
 		return cname.(string), nil
 	}
 
-	cname, err := net.LookupCNAME(domain)
+	query, err := net.LookupCNAME(domain)
 	if err == nil {
-		cnameCache.Set(domain, cname, cache.DefaultExpiration)
-		return cname.(string), nil
+		if query[len(query)-1] == '.' {
+			query = query[:len(query)-1]
+		}
+		cnameCache.Set(domain, query, cache.DefaultExpiration)
+		return query, nil
 	}
 
 	return "", err