CI: add lv_sim workflow and upload 'infinisim' executable

use InfiniSim repo to build simulator in CI

Author: NeroBurner

.github/workflows/lv_sim.yml

@@ -0,0 +1,74 @@
+# GitHub Actions Workflow to build Simulator for PineTime Smart Watch LVGL Interface
+
+# Name of this Workflow
+name: Build PineTime LVGL Simulator
+
+# When to run this Workflow...
+on:
+
+  # Run on all branches
+  push:
+    branches: []
+
+  # Also run this Workflow when a Pull Request is created or updated in the "master" and "develop" Branch
+  pull_request:
+    branches: [ master, develop ]
+
+# Steps to run for the Workflow
+jobs:
+  build:
+
+    # Run these steps on Ubuntu
+    runs-on: ubuntu-latest
+
+    steps:
+
+      #########################################################################################
+      # Download and Install Dependencies
+
+      - name: Install cmake
+        uses: lukka/get-cmake@v3.18.3
+
+      - name: Install SDL2 development package
+        run:  |
+          sudo apt-get update
+          sudo apt-get -y install libsdl2-dev
+
+      #########################################################################################
+      # Checkout
+
+      - name: Checkout source files
+        uses: actions/checkout@v2
+        with:
+          submodules: recursive
+
+      #########################################################################################
+      # get InfiniSim repo
+
+      - name: Get InfiniSim repo
+        run:  |
+          git clone https://github.com/InfiniTimeOrg/InfiniSim.git --depth 1 --branch main
+          git -C InfiniSim submodule update --init lv_drivers
+
+      #########################################################################################
+      # CMake
+
+      - name: CMake
+        run:  |
+          cmake -G Ninja -S InfiniSim -B build_lv_sim -DInfiniTime_DIR="${PWD}"
+
+      #########################################################################################
+      # Build and Upload simulator
+
+      # For Debugging Builds: Remove "make" option "-j" for clearer output. Add "--trace" to see details.
+      # For Faster Builds: Add "make" option "-j"
+
+      - name: Build simulator executable
+        run:  |
+          cmake --build build_lv_sim
+
+      - name: Upload simulator executable
+        uses: actions/upload-artifact@v2
+        with:
+          name: infinisim
+          path: build_lv_sim/infinisim

README.md

@@ -26,6 +26,10 @@ Fast open-source firmware for the [PineTime smartwatch](https://www.pine64.org/p
  - [Creating a stopwatch in Pinetime(article)](https://pankajraghav.com/2021/04/03/PINETIME-STOPCLOCK.html)
  - [Tips on designing an app UI](doc/ui_guidelines.md)
 
+### InfiniSim Simulator
+Use the [InfiniSim Simulator](https://github.com/InfiniTimeOrg/InfiniSim) to experience the `InfiniTime` user interface directly on your PC, to shorten the time until you get your hands on a real [PineTime smartwatch](https://www.pine64.org/pinetime/).
+Or use it to develop new Watchfaces, new Screens, or quickly iterate on the user interface.
+
 ### Contributing
  - [How to contribute?](/doc/contribute.md)
  - [Coding conventions](/doc/coding-convention.md)