Upgrade webR, jupyterlite and expose baseUrl & repoUrl in configuration

[georgestagg]

Fixes #8.

[psychemedia]

HI @georgestagg

The webr_kernel.ts file still declares other R versions?

jupyterlite-webr-kernel/src/webr_kernel.ts

Line 8 in 49e5e06

const webRVersion = "0.3.0";

const webRVersion = "0.3.0";
const baseRVersion = "4.3.3";
const protocolVersion = "5.3";

The baseRVersion should presumably be set from a call to the R wasm package (unless it is used to set the wasm package version) and the webr version should ideally also have some relationship to installing or setting the webr package version?

[georgestagg]

Whoops, thanks for pointing this out!

The versions are now determined dynamically as of commit 4962728.