chore: harden actions & run on main (#942)

Author: lwasser

.github/workflows/build-website.yml

@@ -1,9 +1,9 @@
-name: Deploy to GitHub Pages
+name: Deploy Site to GitHub Pages
 
 on:
   push:
     branches:
-      - docs-upgrade
+      - main
 jobs:
   build:
     name: Build Astro site

.github/workflows/lint.yml

@@ -13,7 +13,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
-      - uses: actions/setup-node@v5
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      - uses: actions/setup-node@dbe1369d7be17e7823f8c1ee1ae8bec5779239dd # v3.9.0
       - run: npm ci
       - run: npm run lint