created action to build pdf

.github/workflows/main.yml

@@ -0,0 +1,23 @@
+name: Deploy PDF
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Compile LaTeX document
+        uses: xu-cheng/latex-action@v3
+        with:
+          root_file: introduction_to_linear_algebra_notes.tex
+
+      - name: Upload PDF file
+        uses: actions/upload-artifact@v3
+        with:
+          name: PDF
+          path: introduction_to_linear_algebra_notes.pdf