fix: set upstream in sync handler, cleanup docs around setting up github

Jacky Zhao

2023-12-15 c35818c336e64e43c54766a670e03cd165b59503

 quartz/cli/handlers.js

@@ -528,7 +528,7 @@
  await popContentFolder(contentFolder)
  if (argv.push) {
    console.log("Pushing your changes")
    const res = spawnSync("git", ["push", "-f", ORIGIN_NAME, QUARTZ_SOURCE_BRANCH], {
    const res = spawnSync("git", ["push", "-uf", ORIGIN_NAME, QUARTZ_SOURCE_BRANCH], {
      stdio: "inherit",
    })
    if (res.status !== 0) {