Set version 0.4.2

Release webR 0.4.1

Release webR 0.4.0 (#452)

* webR 0.4.0-rc.0

* Minor design tweaks for use on mobile devices

* webR 0.4.0

* Update NEWS.md

webR 0.4.0-rc.0

Set version v0.3.3

Set version v0.3.2

Set version v0.3.1

Merge pull request #382 from r-wasm/rel-v0.3.0

Release v0.3.0

Set version v0.3.0-rc.1

Checkout specific webR git commit in Docker CI