build(deps): bump injector from 0.20.1 to 0.21.0 (#60)

Bumps [injector](https://github.com/alecthomas/injector) from 0.20.1 to 0.21.0.
- [Changelog](https://github.com/python-injector/injector/blob/master/CHANGES)
- [Commits](python-injector/injector@0.20.1...0.21.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

poetry.lock

@@ -9,7 +9,7 @@ packages = [{include = "banshee", from = "src"}]
 [tool.poetry.dependencies]
 python = "^3.10"
 exceptiongroup = {version = "^1.0.0-rc.3"}
-injector = {version = ">=0.19,<0.21", optional = true}
+injector = {version = ">=0.19,<0.22", optional = true}
 
 [tool.poetry.group.docs.dependencies]
 myst-parser = ">=0.17.2,<0.19.0"