Release Strata version 2.0.0-alpha.78.
Release Strata version 2.0.0-alpha.78.

 * Use a single Fracture in Sheaf.
 * Upgrade for new Turnstile, Destructible, Fracture.
 * Upgrade `writeahead` to `0.0.10`.
 * Upgrade `fracture` to `0.3.0-alpha.30`.
 * Upgrade `destructible` to `7.0.0-alpha.36`.
 * Upgrade `perhaps` to `0.0.6`.
 * Upgrade `turnstile` to `6.0.0-alpha.48`.

Closes #747.

bigeasy/strata,bigeasy/strata