Bump deps
**NB**: Bump Nippy dependency (2.6.3->2.7.0)
[#107] Experimental: add support for reply suppression

May be useful for higher-level constructs + when performing side effects
that we don't want causing noise in reply pipelines, etc.
[#108] **nb**, experimental: optimize stashed replies to use 1 rather than 2 network roundtrips