split codeql workflow into two files as no compilation is needed for python

.github/workflows/codeql-cpp.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         # Supported options are ['csharp', 'cpp', 'go', 'java', 'javascript', 'python']
-        language: ['cpp', 'python']
+        language: ['cpp']
 
     steps:
     - name: Checkout repository

.github/workflows/codeql-python.yml

@@ -0,0 +1,42 @@
+# GitHub action to run static code analysis on C++ and Python code
+name: "CodeQL Code Analysis"
+
+on:
+  push:
+    branches: [master]
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        # Supported options are ['csharp', 'cpp', 'go', 'java', 'javascript', 'python']
+        language: ['python']
+
+    steps:
+    - name: Checkout repository
+      if: ${{ github.repository == 'lammps/lammps' }}
+      uses: actions/checkout@v2
+      with:
+        # We must fetch at least the immediate parents so that if this is
+        # a pull request then we can checkout the head.
+        fetch-depth: 2
+
+    # If this run was triggered by a pull request event, then checkout
+    # the head of the pull request instead of the merge commit.
+    - run: git checkout HEAD^2
+      if: ${{ github.repository == 'lammps/lammps' && github.event_name == 'pull_request' }}
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      if: ${{ github.repository == 'lammps/lammps' }}
+      uses: github/codeql-action/init@v1
+      with:
+        languages: ${{ matrix.language }}
+
+    - name: Perform CodeQL Analysis
+      if: ${{ github.repository == 'lammps/lammps' }}
+      uses: github/codeql-action/analyze@v1