Update test commands (#1205)

* As per @Yun Feng: everyone has npm installed globally but maybe not yarn

* Add command to enable test result updating

* Default to running tests HEADLESS on rrweb

* Add command to build:all in a low memory environment

* Add a 'retest' command for when the code hasn't changed, but you are working on the test cases

* Add commands to reformat according to prettier. Named 'reformat' to indicate that we are doing a `--write`

* Update package.json

Co-authored-by: Yun Feng <yun.feng0817@gmail.com>

* Apply suggestions from code review

Co-authored-by: Yun Feng <yun.feng0817@gmail.com>

* Create few-turkeys-reflect.md

* Apply formatting changes

---------

Co-authored-by: Justin Halsall <Juice10@users.noreply.github.com>
Co-authored-by: Yun Feng <yun.feng0817@gmail.com>

packages/rrweb-snapshot/package.json

@@ -7,11 +7,12 @@
     "prepack": "npm run bundle && npm run typings",
     "test": "jest",
     "test:watch": "jest --watch",
+    "test:update": "jest --updateSnapshot",
     "bundle": "rollup --config",
     "bundle:es-only": "cross-env ES_ONLY=true rollup --config",
     "dev": "yarn bundle:es-only --watch",
     "typings": "tsc -d --declarationDir typings",
-    "prepublish": "npm run typings && npm run bundle",
+    "prepublish": "yarn typings && yarn bundle",
     "lint": "yarn eslint src"
   },
   "type": "module",