Bump virtualenv from 20.30 to 20.35.4

Bumps [virtualenv](https://github.com/pypa/virtualenv) from 20.30 to 20.35.4.
- [Release notes](https://github.com/pypa/virtualenv/releases)
- [Changelog](https://github.com/pypa/virtualenv/blob/main/docs/changelog.rst)
- [Commits](pypa/virtualenv@20.30.0...20.35.4)

---
updated-dependencies:
- dependency-name: virtualenv
  dependency-version: 20.35.4
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pyproject.toml

@@ -37,7 +37,7 @@ dependencies = [
 [project.optional-dependencies]
 dev = [
     "asv==0.6.5", # Used to compute performance benchmarks
-    "virtualenv==20.30", # Temporary fix to airspeed-velocity/asv#1484
+    "virtualenv==20.35.4", # Temporary fix to airspeed-velocity/asv#1484
     "jupyter", # Clears output from Jupyter notebooks
     "mypy", # Used for static type checking of files
     "pre-commit", # Used to run checks before finalizing a git commit