Bump stacker from 0.1.14 to 0.1.15

Bumps [stacker](https://github.com/rust-lang/stacker) from 0.1.14 to 0.1.15.
- [Release notes](https://github.com/rust-lang/stacker/releases)
- [Commits](rust-lang/stacker@stacker-0.1.14...stacker-0.1.15)

---
updated-dependencies:
- dependency-name: stacker
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.lock

@@ -18,7 +18,7 @@ serde = { version = "1.0.143", features = ["derive"] }
 serde_json = { version = "1.0.91", features = ["preserve_order"] }
 serde_repr = "0.1.8"
 serde-wasm-bindgen = "0.4.3"
-stacker = "0.1.14"
+stacker = "0.1.15"
 wasm-bindgen = "0.2.81"
 rayon = "1.5.3"
 wasm-bindgen-rayon = "1.0.3"