build(deps): 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](matklad/once_cell@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>

Author: dependabot[bot]

Cargo.lock

@@ -12,7 +12,7 @@ indexmap = "1.7"
 Inflector = "0.11.3"
 lazy_static = "1.2.0"
 stable-hash = { git = "https://github.com/graphprotocol/stable-hash" }
-once_cell = "1.8.0"
+once_cell = "1.9.0"
 defer = "0.1"
 parking_lot = "0.11"
 anyhow = "1.0"