chore: v5.30.0 (vega#3934)

Changes since v5.29.0

**vega-functions**
- make default vega format null as "null" (via vega#3926). (Thanks @kanitw &
@domoritz )!

**docs**
- Add 4 new examples (via vega#3851). (Thanks @avatorl & @domoritz!)

**monorepo**
- Deploy editor preview (via vega#3925, vega#3931). (Thanks @hydrosquall!)
- Bump all `vega-*` deps in topological order to eliminate version
mismatches within the monorepo (via vega#3932). (Thanks @lsh!)

Signed-off-by: Lukas Hermann <[email protected]>

chore: bump vega-cli version (vega#3922)

Bump Vega-CLI to the latest release

chore: bump vega version to 5.28.0 (vega#3890)

chore: v5.27.0 (vega#3852)

* chore: bump versions

* chore: bump rollup version

* chore: bump @babel/plugin-transform-runtime

* chore: bump @babel/eslint-parser

* chore: bump jsdom

* chore: bump vega version in docs

* chore: update package versions

* bump package version

* update deps

* chore: bump rollup

* chore: update build files

* chore: bump vega deps versions

* chore: update build files

chore: v5.26.1 (vega#3829)

* chore: Bump package versions.

* docs: Add docs build files.

chore: v5.26.0 (vega#3823)

* chore: Bump dev dependencies.

* chore: Bump package versions.

* docs: Add docs build files.

* chore: Support docs bundle in local folder.

ci: Revert node version change.

docs: Update docs build files.

chore: Update yarn.lock.