get_assets now uses public endpoint

It's better if the data is available through a public endpoint.

piker/brokers/deribit/api.py

@@ -65,6 +65,7 @@ from .venues import (
 )
 from piker.accounting import (
     Asset,
+    digits_to_dec,
     MktPair,
 )
 from piker.data import (
@@ -308,18 +309,16 @@ class Client:
         """
         assets = {}
         resp = await self.json_rpc(
-            'private/get_account_summaries',
-            params={
-                'extended' : True
-            }
+            'public/get_currencies',
+            params={}
         )
-        summaries = resp.result['summaries']
-        for summary in summaries:
-            currency = summary['currency']
-            tx_tick = Decimal('1e-08')
+        currencies = resp.result
+        for currency in currencies:
+            name = currency['currency']
+            tx_tick = digits_to_dec(currency['fee_precision']) 
             atype='crypto_currency'
-            assets[currency] = Asset(
-                name=currency,
+            assets[name] = Asset(
+                name=name,
                 atype=atype,
                 tx_tick=tx_tick)
         return assets 
@@ -461,7 +460,6 @@ class Client:
             limit=limit
         )
 
-
     async def bars(
         self,
         mkt: MktPair,