DevOps-Cheatsheet: 🚀 Fixed workflow failure due to deprecated actions

- Upgraded `actions/upload-artifact` from `v3` to `v4` to resolve deprecation error
- Updated `actions/checkout` to `v4` for best practices
- Ensured workflow remains functional for generating and uploading PDFs

Signed-off-by: ProDevOpsGuy Tech <[email protected]>
Signed-off-by: NotHarshhaa <[email protected]>

Author: prodevopsguytech

.github/workflows/generate-pdf.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install pandoc and LaTeX
       run: |
@@ -30,7 +30,7 @@ jobs:
         done
 
     - name: Upload PDF artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: pdfs
         path: '**/*.pdf'