Switches testing and the build pipeline to node 20 (#68)

The start of verifying that all of the spur tooling works with node 20. We don't transpile so it's mainly for testing purposes.

Will still verify with node 16, and 18.

.github/workflows/npm-publish.yml

@@ -10,7 +10,7 @@ jobs:
       # Setup .npmrc file to publish to npm
       - uses: actions/setup-node@v3
         with:
-          node-version: '18.x'
+          node-version: '20.x'
           registry-url: 'https://registry.npmjs.org'
       - run: npm ci
       - run: npm publish

.github/workflows/pull-request.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x, 18.x]
+        node-version: [16.x, 18.x, 20.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps:

.nvmrc

@@ -1 +1 @@
-18
+20