cargo: bump once_cell from 1.8.0 to 1.9.0

Bumps [once_cell](https://github.com/matklad/once_cell) from 1.8.0 to 1.9.0.
- [Release notes](https://github.com/matklad/once_cell/releases)
- [Changelog](https://github.com/matklad/once_cell/blob/master/CHANGELOG.md)
- [Commits](https://github.com/matklad/once_cell/compare/v1.8.0...v1.9.0)

---
updated-dependencies:
- dependency-name: once_cell
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Cargo.lock

@@ -2407,9 +2407,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.8.0"
+version = "1.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
+checksum = "da32515d9f6e6e489d7bc9d84c71b060db7247dc035bbe44eac88cf87486d8d5"
 
 [[package]]
 name = "oorandom"

Cargo.toml

@@ -45,7 +45,7 @@ native-tls = "0.2"
 num_cpus = "1.13"
 num-derive = "0.3"
 num-traits = "0.2"
-once_cell = "1.8.0"
+once_cell = "1.9.0"
 percent-encoding = "2.0"
 pgp = { version = "0.7", default-features = false }
 pretty_env_logger = { version = "0.4", optional = true }