Don't upload multiple times to same artifact in sketch compilation workflow

The "Compile Examples" GitHub Actions workflow is configured to compile the example sketches for each of the supported
boards. This is done by using a job matrix in the GitHub Actions workflow to generate a parallel job for each board.

A GitHub Actions workflow artifact is used to transfer the sketches report files generated by the
"arduino/compile-sketches" action between this workflow's job and the "Report Size Deltas" workflow that uses the
"arduino/report-size-deltas" action to publish the data. The "actions/upload-artifact" action is used to upload the
sketches report files to the workflow artifact.

Previously, the sketches reports from all the boards were uploaded to a single artifact. However, support for uploading
multiple times to a single artifact was dropped in version 4.0.0 of the "actions/upload-artifact" action. So it is now
necessary for each of the jobs to use a separate artifact. The "arduino/report-size-deltas" action is configured to
recognize these multiple artifacts by a regular expression that matches against a standardized prefix on the artifact
names.

Author: per1234

.github/workflows/compile-examples.yml

@@ -57,8 +57,10 @@ jobs:
         board:
           - fqbn: arduino:mbed_portenta:envie_m7
             platform-name: arduino:mbed_portenta
+            artifact-name-suffix: arduino-mbed_portenta-envie_m7
           - fqbn: arduino:mbed_giga:giga
             platform-name: arduino:mbed_giga
+            artifact-name-suffix: arduino-mbed_giga-giga
 
         include:
           - board:
@@ -99,6 +101,6 @@ jobs:
       - name: Save memory usage change report as artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ env.SKETCHES_REPORTS_PATH }}
+          name: sketches-report-${{ matrix.board.artifact-name-suffix }}
           if-no-files-found: error
           path: ${{ env.SKETCHES_REPORTS_PATH }}

.github/workflows/report-size-deltas.yml

@@ -20,5 +20,5 @@ jobs:
       - name: Comment size deltas reports to PRs
         uses: arduino/report-size-deltas@v1
         with:
-          # The name of the workflow artifact created by the "Compile Examples" workflow
-          sketches-reports-source: sketches-reports
+          # Regex matching the names of the workflow artifacts created by the "Compile Examples" workflow
+          sketches-reports-source: ^sketches-report-.+