Add audit 57

audit/var-57.md

+# Chain Variable Transaction 57
+
+## Changes
+
+This transaction sets the `poc_addr_hash_byte_count` to 8.
+
+## Version threshold
+
+None
+
+## Transaction
+
+```
+{blockchain_txn_vars_v1_pb,
+    [{blockchain_var_v1_pb,"poc_addr_hash_byte_count","int",
+         <<"8">>}],
+    0,
+    <<48,69,2,33,0,221,250,95,93,50,219,230,110,119,255,252,
+      156,234,14,75,15,198,133,95,34,123,183,7,132,121,35,226,
+      88,189,145,31,24,2,32,107,48,6,39,160,163,103,48,226,
+      148,94,191,228,183,160,116,3,195,108,23,177,131,228,165,
+      229,102,153,84,220,112,142,76>>,
+    <<>>,<<>>,[],[],57,[],[],[]}
+```
+
+## Acceptance block
+
+751961
+
+## Acceptance block time
+
+Tue Mar 09 03:53:38 PM UTC 2021