update WASI submodule (#3025)

* wasi-common: update wasi submodule

This updates the WASI submodule, pulling in changes to the witx crate,
now that there is a 0.9.1 version including some bug fixes. See
WebAssembly/WASI#434 for more information.

* wiggle: update witx dependencies

* publish: verify and vendor witx-cli

* adjust root workspace members

This commit removes some items from the root manifest's workspace
members array, and adds `witx-cli` to the root `workspace.exclude`
array.

The motivation for this stems from a cargo bug described in
rust-lang/cargo#6745: `workspace.exclude` does not work if it is nested
under a `workspace.members` path.

See WebAssembly/WASI#438 for the underlying change to the WASI submodule
which reorganized the `witx-cli` crate, and WebAssembly/WASI#398 for the
original PR introducing `witx-cli`.

See [this
comment](https://github.com/bytecodealliance/wasmtime/pull/3025#issuecomment-867741175)
for more details about the compilation errors, and failed alternative
approaches that necessitated this change.

N.B. This is not a functional change, these crates are still implicitly
workspace members as transitive dependencies, but this will allow us to
side-step the aforementioned cargo bug.

Co-Authored-By: Alex Crichton <alex@alexcrichton.com>

Co-authored-by: Alex Crichton <alex@alexcrichton.com>

Cargo.lock

@@ -986,12 +986,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "diff"
-version = "0.1.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e25ea47919b1560c4e3b7fe0aaab9becf5b84a10325ddf7db0f0ba5e1026499"
-
 [[package]]
 name = "digest"
 version = "0.9.0"
@@ -3855,9 +3849,9 @@ dependencies = [
 
 [[package]]
 name = "wast"
-version = "33.0.0"
+version = "35.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d04fe175c7f78214971293e7d8875673804e736092206a3a4544dbc12811c1b"
+checksum = "2ef140f1b49946586078353a453a1d28ba90adfc54dde75710bc1931de204d68"
 dependencies = [
  "leb128",
 ]
@@ -3986,16 +3980,13 @@ dependencies = [
 
 [[package]]
 name = "witx"
-version = "0.9.0"
+version = "0.9.1"
 dependencies = [
  "anyhow",
- "diff",
  "log",
- "pretty_env_logger",
  "rayon",
- "structopt",
  "thiserror",
- "wast 33.0.0",
+ "wast 35.0.2",
 ]
 
 [[package]]