update github workflows

Author: s-dakshin

.github/workflows/Emscripten.yaml

@@ -8,7 +8,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@main
 
       - name: Checkout submodules
         run: git submodule update --init --recursive

CMakeLists.txt

@@ -22,7 +22,7 @@ set(CMAKE_CXX_STANDARD 17)
 # i/ You can install hello_imgui via vcpkg with:
 #     vcpkg install "hello-imgui[opengl3-binding,glfw-binding]"
 # ii/ Then you can use it inside CMake with:
-#      find_package(hello-imgui CONFIG REQUIRED)
+#     find_package(hello-imgui CONFIG REQUIRED)
 
 # ============================================================================
 # Add dependencies via CPM (cmake/tools.cmake includes cmake/CPM.cmake)