[Subscriptions API] Multiple dialects in the filter object (#803)
[Subscriptions API] Multiple dialects in the filter object (#803)

* Now filter accepts an array of expressions, and it does the and of them
Renamed filter to filters

Signed-off-by: Francesco Guardiani <56fdeb8ec48293e404ca3681b2b8738f930aab75@gmail.com>

* Nit

Signed-off-by: Francesco Guardiani <56fdeb8ec48293e404ca3681b2b8738f930aab75@gmail.com>

* Support empty array

Signed-off-by: Francesco Guardiani <56fdeb8ec48293e404ca3681b2b8738f930aab75@gmail.com>
cloudevents/spec