fix: Fails to load import map with module URL starting with "./"

[aiotter]

Lume fails to parse import map like following:

{
  "imports": {
    "/": "./"
}

// Import map diagnostics:
//   - Invalid address "./" for the specifier key "/".

This is because Lume parses the given import map and convert it to data URI scheme.
Data URI scheme has no base URL, so parsing this specifier fails.

lume/ci.ts

Lines 45 to 70 in 5f0d950

	export async function getImportMap(mapFile?: string) {
	const map: ImportMap = {
	imports: {
	"lume": join(baseUrl, "/mod.ts"),
	"lume/": join(baseUrl, "/"),
	"https://deno.land/x/lume/": join(baseUrl, "/"),
	},
	};
	if (mapFile) {
	try {
	const url = await ensureUrl(mapFile);
	const file = await (await fetch(url)).text();
	const parsedMap = JSON.parse(file) as ImportMap;
	map.imports = { ...map.imports, ...parsedMap.imports };
	map.scopes = parsedMap.scopes;
	} catch (cause) {
	throw new Exception("Unable to load the import map file", {
	cause,
	mapFile,
	});
	}
	}
	return `data:application/json;base64,${encode(JSON.stringify(map))}`;
	}

On deno environment, module URL which starts with "./" should be resolved to the import map's URL.
https://deno.land/manual/linking_to_external_code/import_maps

This PR fixes this issue by resolving those relative paths into file URI schemes.

[aiotter]

I've never seen checkout@v2 fails.
Can you re-run the workflow? I believe this is a temporary problem.

[oscarotero]

Thanks, it looks good.
I think the test error is not related with this.