docs: update version, deps and docs for 8.0 beta (#849)

* chore: up version and deps

* chore: use pnpm CLI to get versions

* add note for echarts 6 upgrade guide

* remove docs script

let cdn to redirect for us

* Revert "remove docs script"

This reverts commit 3bc237db9100864f2813249ac1693735a658e646.

* update demo links

scripts/utils.ts

@@ -0,0 +1,20 @@
+import { execSync } from "node:child_process";
+import { resolve, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+export function resolvePath(url: string, ...parts: string[]) {
+  return resolve(dirname(fileURLToPath(url)), ...parts);
+}
+
+type PackageVersions = {
+  name: string;
+  version: string;
+  devDependencies: Record<string, { version: string }>;
+};
+
+export function getPackageVersions(devDeps?: string[]): PackageVersions {
+  const stdOut = execSync(`pnpm ls ${devDeps?.join(" ") || ""} --json`, {
+    encoding: "utf-8",
+  });
+  return JSON.parse(stdOut)[0];
+}