CoinbasePro ticker issue

[bucherarnold]

CoinbasePro ticker is not supported for ETH/GBP currency pair:

Note:
CoinbaseProMarketDataServiceRaw:checkProductExists() will return false in case of ETH/GBP currency pair.
exchange.getExchangeSymbols() not returns all supported currency pairs

[cymp]

This can come from the fact that the symbols are sometimes read from a hard coded json in XChange. The reason can be:

• There are not available from the API
• They are, but the the remoteInit does not call the API endpoint

Both case would require a PR.

[jakubkalicki]

Hey @bucherarnold, @timmolter,
I wanted to fix this, but seems like issue is already solved.

[earce]

This can be closed as seems to be resolved.