extmod/uzlib: Update to upstream v2.1.

Adds check that LZ offsets fall into the sliding dictionary used. This
catches a case when uzlib.DecompIO with a smaller dictionary is used
to decompress data which was compressed with a larger dictionary.
Previously, this would lead to producing invalid data or crash, now
an exception will be thrown.

extmod/uzlib/tinf.h

@@ -32,6 +32,7 @@ extern "C" {
 #define TINF_DONE           1
 #define TINF_DATA_ERROR    (-3)
 #define TINF_CHKSUM_ERROR  (-4)
+#define TINF_DICT_ERROR    (-5)
 
 /* checksum types */
 #define TINF_CHKSUM_NONE  0

extmod/uzlib/tinflate.c

@@ -361,6 +361,9 @@ static int tinf_inflate_block_data(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
         /* possibly get more bits from distance code */
         offs = tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
         if (d->dict_ring) {
+            if (offs > d->dict_size) {
+                return TINF_DICT_ERROR;
+            }
             d->lzOff = d->dict_idx - offs;
             if (d->lzOff < 0) {
                 d->lzOff += d->dict_size;