Quick change to standardize on a single timezone across all workflows
and to use the same version of node (18.20.1).
Also updates .nvmrc
ghstack-source-id: e1d43006ec
Pull Request resolved: https://github.com/facebook/react/pull/30323
- Made each workflow's name consistent
- Rename each workflow file with consistent naming scheme
- Promote flow-ci-ghaction to flow-ci
ghstack-source-id: 490b643dcd
Pull Request resolved: https://github.com/facebook/react/pull/30037
