Release Preview 2: set package version to 0.2.0

[pchickey]

And update dependency for wasi-io, wasi-clocks, wasi-random, wasi-filesystem, and wasi-sockets to 0.2.0.

TODO:

• [x] run wit-deps update once the following PRs have landed:
  • https://github.com/WebAssembly/wasi-random/pull/40
  • https://github.com/WebAssembly/wasi-filesystem/pull/144
  • https://github.com/WebAssembly/wasi-sockets/pull/99