Fixed `PinsAddArguments` and `PinsRemoveArguments` interface (#1277)
Fixed `PinsAddArguments` and `PinsRemoveArguments` interface (#1277)

* Fixed `PinsAddArguments` interface

* also updated `PinsRemoveArguments`
slackapi/node-slack-sdk,slackapi/node-slack-sdk,slackapi/node-slack-sdk,slackapi/node-slack-sdk