chore(deps): bump @snapshot-labs/eslint-config-base

Bumps @snapshot-labs/eslint-config-base from 0.1.0-beta.18 to 0.1.0-beta.21.

---
updated-dependencies:
- dependency-name: "@snapshot-labs/eslint-config-base"
  dependency-version: 0.1.0-beta.21
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]