Update of `servant-tezos-api` version and increase price worker interval to 60s
This addresses two issues in Caldera found on April 27th:
- We get "429 Too Many Requests" from CoinGecko . That would only affect values given in these currencies from CoinGecko. (I see JPY and KRW in the logs.)
- It looks like Caldera worker cannot request head block, because JSON response format fails.
First is addressed by increasing default interval to 60s (or should we take 5 minutes or an hour?), second is addressed by update to servant-tezos-api#6.