build(deps): bump structopt from 0.3.17 to 0.3.18

Bumps [structopt](https://github.com/TeXitoi/structopt) from 0.3.17 to 0.3.18.
- [Release notes](https://github.com/TeXitoi/structopt/releases)
- [Changelog](https://github.com/TeXitoi/structopt/blob/master/CHANGELOG.md)
- [Commits](https://github.com/TeXitoi/structopt/compare/v0.3.17...v0.3.18)

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

Cargo.lock

@@ -2505,9 +2505,9 @@ checksum = "6446ced80d6c486436db5c078dde11a9f73d42b57fb273121e160b84f63d894c"
 
 [[package]]
 name = "structopt"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6cc388d94ffabf39b5ed5fadddc40147cb21e605f53db6f8f36a625d27489ac5"
+checksum = "a33f6461027d7f08a13715659b2948e1602c31a3756aeae9378bfe7518c72e82"
 dependencies = [
  "clap",
  "lazy_static",
@@ -2516,9 +2516,9 @@ dependencies = [
 
 [[package]]
 name = "structopt-derive"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e2513111825077552a6751dfad9e11ce0fba07d7276a3943a037d7e93e64c5f"
+checksum = "c92e775028122a4b3dd55d58f14fc5120289c69bee99df1d117ae30f84b225c9"
 dependencies = [
  "heck",
  "proc-macro-error",

zebra-utils/Cargo.toml

@@ -8,7 +8,7 @@ edition = "2018"
 publish = false
 
 [dependencies]
-structopt = "0.3.17"
+structopt = "0.3.18"
 color-eyre = "0.5.3"
 hex = "0.4"
 serde_json = "1.0"