Bump mdbook from 0.4.21 to 0.4.22dependabot/cargo/mdbook-0.4.22

Bumps [mdbook](https://github.com/rust-lang/mdBook) from 0.4.21 to 0.4.22.
- [Release notes](https://github.com/rust-lang/mdBook/releases)
- [Changelog](https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/mdBook/compare/v0.4.21...v0.4.22)

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

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

1 files changed, 3 insertions, 3 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 6925573..ccd39e7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -822,9 +822,9 @@ dependencies = [
 
 [[package]]
 name = "mdbook"
-version = "0.4.21"
+version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23f3e133c6d515528745ffd3b9f0c7d975ae039f0b6abb099f2168daa2afb4f9"
+checksum = "6b61566b406cbd75d81c634763d6c90779ca9db80202921c884348d172ada70d"
 dependencies = [
  "ammonia",
  "anyhow",
@@ -836,10 +836,10 @@ dependencies = [
  "futures-util",
  "gitignore",
  "handlebars",
- "lazy_static",
  "log",
  "memchr",
  "notify",
+ "once_cell",
  "opener",
  "pulldown-cmark",
  "regex",