Add workflow and info about CPM

.github/workflows/update-lua.yml

@@ -0,0 +1,41 @@
+name: Update Lua Submodule
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "*/5 * * * *"
+
+permissions:
+  contents: write
+
+concurrency:
+  group: update-modules-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  update-modules:
+    name: Update Modules
+    runs-on: ubuntu-latest
+
+    # https://stackoverflow.com/questions/64407333/using-github-actions-to-automatically-update-the-repos-submodules
+    defaults:
+      run:
+        shell: bash
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+      with:
+        submodules: true
+
+    - name: Pull and Update Submodules
+      run: |
+        git pull --recurse-submodules
+        git submodule update --remote --recursive
+
+    - name: Commit Update
+      run: |
+        git config --global user.name 'Lua Submodule Updater'
+        git config --global user.email '[email protected]'
+        git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }}
+        git commit -am "Update Lua" && git push || echo "No changes to commit"

README.md

@@ -21,7 +21,15 @@ on `cmake`'s
 [`BUILD_SHARED_LIBS`](https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html) flag. No
 `install` target is configured and no standalone executable is built, given the intended use case.
 
-Here's how to use it:
+# How to use it:
+## CPM
+In the `CMakeLists.txt` of your application, add
+```
+CPMAddPackage("gh:lubgr/lua-cmake#master")
+
+target_link_libraries(yourTarget PRIVATE lua::lib)
+```
+## Git Submodules
 ```bash
 cd path/to/your/project
 
@@ -36,5 +44,6 @@ add_subdirectory(external/lua)
 
 target_link_libraries(yourTarget PRIVATE lua::lib)
 ```
+------------------------------------------------------------------------
 That's it. Further integration with a library to facilitate the bindings (e.g.
 [sol2](https://github.com/ThePhD/sol2)) is straightfoward.