change minimum version of Node.js to version 20 (#4978)

* update workflows

* update supported engines in package.json

* .nvmrc

* base yarn cache on node version being used rather than .nvmrc

* note

.github/workflows/check.yml

@@ -43,6 +43,6 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: '19'
+          node-version: 20
       - name: Check migrations
         run: node ./.github/actions/check-migrations.js