add standalone workflow

.github/workflows/standalone.yml

@@ -0,0 +1,20 @@
+name: Standalone
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v1
+    
+    - name: configure
+      run: cmake -Hstandalone -Bbuild
+
+    - name: build
+      run: cmake --build build/standalone
+
+    - name: run
+      run: ./build/standalone/Greeter

CMakeLists.txt

@@ -37,7 +37,6 @@ CPMAddPackage(
 
 # Note:
 # for single header libraries use `add_library(Greeter INTERFACE)` instead 
-# To create an executable use `add_executable(Greeter ${headers} ${sources})`
 add_library(Greeter ${headers} ${sources})
 
 # Note: for single header libraries use the following instead: