chore: Update CI workflow (typescript-cheatsheets#654)

- Bump actions/checkout to v4.
- Update deprecated set-output command.

Author: abhiram6121

.github/workflows/main.yml

@@ -10,10 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout commit
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Read .nvmrc
-        run: echo ::set-output name=NVMRC::$(cat .nvmrc)
+        run: echo "NVMRC=$(cat .nvmrc)" >> $GITHUB_OUTPUT
         id: nvm
 
       - name: Setup node