Temporarily ignore multiple versions of criterion's build dependencies

Until japaric/cast.rs#26 is resolved, the `cast`
crate will pull in older versions of the `rustc_version`, `semver`, and
`semver-parser` crates. `cast` is a build dependency of `criterion`
which is used for benchmarking and is itself a dev dependency, not a
normal dependency.

deny.toml

@@ -45,4 +45,7 @@ skip = [
     { name = "wast" }, # old one pulled in by witx
     { name = "itertools" }, # 0.9 pulled in by zstd-sys
     { name = "quick-error" }, # transitive dependencies
+    { name = "rustc_version" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
+    { name = "semver" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
+    { name = "semver-parser" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
 ]