ci: split pdf workflow

.github/workflows/sphinx-build-pdf.yaml

@@ -0,0 +1,22 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9 
+    - name: Install Requirements
+      run: |
+        pip install --upgrade pip 
+        pip install -r requirements.txt
+    - name: Sphinx build - pdf
+      run: |
+        sudo apt-get install -y latexmk texlive-full
+        make latexpdf

.github/workflows/sphinx-build.yaml

@@ -19,10 +19,6 @@ jobs:
     - name: Sphinx build - html
       run: |
         make html
-    - name: Sphinx build - pdf
-      run: |
-        sudo apt-get install -y latexmk texlive-latex-extra
-        make latexpdf
     - name: Sphinx build - epub
       run: |
         make epub