Fix `get_message_actions` response (pubnub#141)

fix: fix `get_message_actions` response

Fix format which is used to return server data from `get_message_actions` method call.

build(github-actions): update command processor target

Update name of account to which commands should be sent.

Add message actions api (pubnub#140)

feat(message-actions): add message actions api

Add api which allow to work with message actions endpoints.

test(github-actions): migrate to GitHub actions

Migrate test suite run from Travis to GitHub Actions.

fix(delete-messages): fix issue with channel encoding (pubnub#137)

fix(delete-messages): fix issue with channel encoding

Fix issue because of which channel hasn't been encoded properly with endpoint call.

Fix default `callback` and `http_sync` (pubnub#136)

fix(events): fix default `callback` and `http_sync`

Fix issue because of which `callback` and `http_sync` provided during client configuration not
used when missing in method call.

Add spaces_permissions and users_permissions to grant_token (pubnub#131)

Make uuid mandatory (pubnub#127)

Revoke token (pubnub#124)

Add revoke token

Fix paged history (pubnub#125)

feat(history): add 'all_history_messages'

Add new method `all_history_messages` which return messages from requested interval or
since / before date in single object.

fix(history): fix paged history

Fix exception raised when optional start / end not passed to `paged_history`.

PAMv3 implementation (pubnub#122)

PubNub SDK v4.6.2 release.