Update wabt requirement from 0.7 to 0.8

Updates the requirements on [wabt](https://github.com/pepyakin/wabt-rs) to permit the latest version.
- [Release notes](https://github.com/pepyakin/wabt-rs/releases)
- [Commits](https://github.com/pepyakin/wabt-rs/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

wasmtime-wast/Cargo.toml

@@ -19,7 +19,7 @@ cranelift-entity = "0.33.0"
 wasmtime-jit = { path = "../wasmtime-jit" }
 wasmtime-runtime = { path = "../wasmtime-runtime" }
 wasmtime-environ = { path = "../wasmtime-environ" }
-wabt = "0.7"
+wabt = "0.8"
 target-lexicon = "0.4.0"
 failure = { version = "0.1.3", default-features = false }
 failure_derive = { version = "0.1.3", default-features = false }