Add step to install repo as Arduino library

Added a step to install the repository as a library in the Arduino environment.

.github/workflows/main.yml

@@ -57,6 +57,11 @@ jobs:
         run: |
           arduino-cli core update-index
           arduino-cli core install ${{ matrix.arduino-platform }}
+      - name: Install repo as library
+        run: |
+          mkdir -p "$HOME/Arduino/libraries"
+          ln -s "$PWD" "$HOME/Arduino/libraries/."
+      
       # Finally, we compile the sketch, using the FQBN that was set
       # in the build matrix.
       - name: Compile Sketch