website: add trailing slash config

.github/workflows/deploy.yml

@@ -46,10 +46,10 @@ jobs:
           git config --global user.name "gh-actions"
           cd website
           if [ -e yarn.lock ]; then
-          yarn install --frozen-lockfile
+            yarn install --frozen-lockfile
           elif [ -e package-lock.json ]; then
-          npm ci
+            npm ci
           else
-          npm i
+            npm i
           fi
           npm run deploy

website/docusaurus.config.js

@@ -3,6 +3,7 @@ module.exports = {
   tagline: 'Curated interview preparation materials for busy engineers',
   url: 'https://techinterviewhandbook.org',
   baseUrl: '/',
+  trailingSlash: true,
   favicon: 'img/favicon.png',
   organizationName: 'yangshun',
   projectName: 'tech-interview-handbook',