Add simple demonstration workflow for pull_request-triggered workflow

A demonstration workflow is provided in the readme to show how to use the action in the use case where the report
workflow is triggered by `pull_request` event.

Previously, this workflow demonstrated the more advanced configuration that is required in order to compile for multiple
boards. Although this demonstration will be useful to the action users, it might be overwhelming as an introduction to
the action usage. A demonstration that only compiles for a single board can be far more simple. Even if the user
requires coverage of multiple boards in their application, this will give them a basic understanding of the action
usage.

The advanced demonstration workflow is hereby moved to the FAQ document, replaced in the readme by a simple
demonstration workflow. A link from the readme to the advanced usage demonstration is provided.

Author: per1234

README.md

@@ -114,51 +114,24 @@ jobs:
 
 ```yaml
 on: [push, pull_request]
-env:
-  # It's convenient to set variables for values used multiple times in the workflow
-  SKETCHES_REPORTS_PATH: sketches-reports
 jobs:
   compile:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        board:
-          - fqbn: arduino:avr:uno
-            artifact-name-suffix: arduino-avr-uno
-          - fqbn: arduino:samd:mkrzero
-            artifact-name-suffix: arduino-samd-mkrzero
     steps:
       - uses: actions/checkout@v4
-
       - uses: arduino/compile-sketches@v1
         with:
-          fqbn: ${{ matrix.board.fqbn }}
           enable-deltas-report: true
-          sketches-report-path: ${{ env.SKETCHES_REPORTS_PATH }}
+      - uses: arduino/report-size-deltas@v1
+        # Only run the action when the workflow is triggered by a pull request.
+        if: github.event_name == 'pull_request'
+```
 
-      # This step is needed to pass the size data to the report job
-      - name: Upload sketches report to workflow artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: sketches-reports-${{ matrix.board.artifact-name-suffix }}
-          path: ${{ env.SKETCHES_REPORTS_PATH }}
+---
 
-  # When using a matrix to compile for multiple boards, it's necessary to use a separate job for the deltas report
-  report:
-    needs: compile # Wait for the compile job to finish to get the data for the report
-    if: github.event_name == 'pull_request' # Only run the job when the workflow is triggered by a pull request
-    runs-on: ubuntu-latest
-    steps:
-      # This step is needed to get the size data produced by the compile jobs
-      - name: Download sketches reports artifacts
-        uses: actions/download-artifact@v4
-        with:
-          path: ${{ env.SKETCHES_REPORTS_PATH }}
+**ⓘ** A more advanced example is available in [the **FAQ**](docs/FAQ.md#workflow-triggered-by-pull_request-event).
 
-      - uses: arduino/report-size-deltas@v1
-        with:
-          sketches-reports-source: ${{ env.SKETCHES_REPORTS_PATH }}
-```
+---
 
 ## Additional resources
 

docs/FAQ.md

@@ -139,3 +139,63 @@ flowchart TB
     reportAction --> comment
   end
 ```
+
+### Workflow triggered by `pull_request` event
+
+```yaml
+on:
+  - push
+  - pull_request
+
+env:
+  # It's convenient to set variables for values used multiple times in the workflow.
+  SKETCHES_REPORTS_PATH: sketches-reports
+
+jobs:
+  compile:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        board:
+          # Each element in the sequence produces a matrix job:
+          - fqbn: arduino:avr:uno
+            # This suffix will be used to define a unique name for the sketches report artifact.
+            artifact-name-suffix: arduino-avr-uno
+          - fqbn: arduino:samd:mkrzero
+            artifact-name-suffix: arduino-samd-mkrzero
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: arduino/compile-sketches@v1
+        with:
+          fqbn: ${{ matrix.board.fqbn }}
+          enable-deltas-report: true
+          sketches-report-path: ${{ env.SKETCHES_REPORTS_PATH }}
+
+      # This step is needed to pass the size data to the report job.
+      - name: Upload sketches report to workflow artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: sketches-reports-${{ matrix.board.artifact-name-suffix }}
+          path: ${{ env.SKETCHES_REPORTS_PATH }}
+
+  # When using a matrix to compile for multiple boards, it's necessary to use a separate job for the deltas report
+  report:
+    needs: compile # Wait for the compile job to finish to get the data for the report
+    if: github.event_name == 'pull_request' # Only run the job when the workflow is triggered by a pull request
+    runs-on: ubuntu-latest
+
+    steps:
+      # This step is needed to get the size data produced by the compile jobs
+      - name: Download sketches reports artifacts
+        uses: actions/download-artifact@v4
+        with:
+          # All workflow artifacts will be downloaded to this location.
+          path: ${{ env.SKETCHES_REPORTS_PATH }}
+
+      - uses: arduino/report-size-deltas@v1
+        with:
+          sketches-reports-source: ${{ env.SKETCHES_REPORTS_PATH }}
+```