Fix String overflow warning

Scanner Output
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rror: COMPILER_WARNING (CWE-758): [#def2]
libtasn1-4.16.0/lib/element.c: scope_hint: In function '_asn1_append_sequence_set'
libtasn1-4.16.0/lib/element.c:186:7: warning[-Wstringop-overflow=]: '_asn1_ltostr' accessing 22 bytes in a region of size 21
 #  186 |       _asn1_ltostr (n, temp + 1);
 #      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~
libtasn1-4.16.0/lib/element.c:186:7: note: referencing argument 2 of type 'char *'
libtasn1-4.16.0/lib/element.c:30: included_from: Included from here.
libtasn1-4.16.0/lib/parser_aux.h:70:7: note: in a call to function '_asn1_ltostr'
 #   70 | char *_asn1_ltostr (int64_t v, char str[LTOSTR_MAX_SIZE]);
 #      |       ^~~~~~~~~~~~
 #  184|         n++;
 #  185|         temp[0] = '?';
 #  186|->       _asn1_ltostr (n, temp + 1);
 #  187|       }
 #  188|     _asn1_set_name (p2, temp);

Signed-off-by: Simo Sorce <simo@redhat.com>
diff --git a/lib/element.c b/lib/element.c
index c4e5180..550fdb2 100644
--- a/lib/element.c
+++ b/lib/element.c
@@ -142,7 +142,7 @@
 _asn1_append_sequence_set (asn1_node node, struct node_tail_cache_st *pcache)
 {
   asn1_node p, p2;
-  char temp[LTOSTR_MAX_SIZE];
+  char temp[LTOSTR_MAX_SIZE+1];
   long n;
 
   if (!node || !(node->down))