feat(nvm): add support for nvm & minor actions housekeeping (#2979)

* feat: add `.nvmrc` for specifying node version

Co-Authored-By: Evandro Leopoldino Gonçalves <evandrolgoncalves@gmail.com>

* chore(deps): bump setup-node to v4

* build: use node-version-file instead of hardcoded 18.x

* chore(deps): bump nvm version

* fix: checkout before install 🎉

---------

Co-authored-by: Evandro Leopoldino Gonçalves <evandrolgoncalves@gmail.com>

bskyweb/README.md

@@ -6,9 +6,9 @@ To build the SPA bundle (`bundle.web.js`), first get a JavaScript development
 environment set up. Either follow the top-level README, or something quick
 like:
 
-    # install nodejs 18 (specifically)
-    nvm install 18
-    nvm use 18
+    # install nodejs
+    nvm install
+    nvm use
     npm install --global yarn
 
     # setup tools and deps (in top level of this repo)