Don't upload multiple times to same artifact in "Release" workflow

The "Release" GitHub Actions workflow generates binaries for a range of target hosts. This is done by using a job matrix
that produces each build in a parallel job. GitHub Actions workflow artifacts are used to transfer the generated files
between sequential jobs in the workflow. The "actions/upload-artifact" and "actions/download-artifact" actions are used
for this purpose.

Previously, a single artifact was used for this purpose, with each of the parallel jobs uploading its own generated
files to that 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 to use a dedicated artifact for each of the builds.
These can be downloaded in aggregate by using the artifact name globbing and merging features which were introduced in
version 4.1.0 of the "actions/download-artifact" action.

Author: per1234

.github/workflows/release.yml

@@ -4,7 +4,7 @@ env:
   # The name of the project
   PROJECT_NAME: imgtool
   DIST_DIR: dist
-  ARTIFACT_NAME: dist
+  ARTIFACT_PREFIX: dist-
   # The project's folder on Arduino's download server for uploading builds
   AWS_PLUGIN_TARGET: /tools/
   # See: https://github.com/actions/setup-python/tree/main#available-versions-of-python
@@ -112,7 +112,7 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           if-no-files-found: error
-          name: ${{ env.ARTIFACT_NAME }}
+          name: ${{ env.ARTIFACT_PREFIX }}${{ matrix.package_platform }}
           path: ${{ env.MCUBOOT_PATH }}/scripts/dist/${{ env.PROJECT_NAME }}_*
 
   build-crosscompile:
@@ -183,23 +183,31 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           if-no-files-found: error
-          name: ${{ env.ARTIFACT_NAME }}
+          name: ${{ env.ARTIFACT_PREFIX }}${{ matrix.package_platform }}
           path: ${{ env.MCUBOOT_PATH }}/scripts/dist/${{ env.PROJECT_NAME }}_*
 
   notarize-macos:
     runs-on: macos-latest
     needs: build
 
+    env:
+      ARTIFACT_SUFFIX: macOS_64bit
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Download artifacts
+      - name: Download non-notarized artifact
         uses: actions/download-artifact@v4
         with:
-          name: ${{ env.ARTIFACT_NAME }}
+          name: ${{ env.ARTIFACT_PREFIX }}${{ env.ARTIFACT_SUFFIX }}
           path: ${{ env.DIST_DIR }}
 
+      - name: Remove non-notarized artifact
+        uses: geekyeggo/delete-artifact@v5
+        with:
+          name: ${{ env.ARTIFACT_PREFIX }}${{ env.ARTIFACT_SUFFIX }}
+
       - name: Import Code-Signing Certificates
         env:
           KEYCHAIN: "sign.keychain"
@@ -248,11 +256,11 @@ jobs:
           PACKAGE_FILENAME="${{ env.PROJECT_NAME }}_${TAG}_macOS_64bit.tar.gz"
           tar -czvf "${PACKAGE_FILENAME}" "${{ env.PROJECT_NAME }}_macOS_64bit"
 
-      - name: Upload artifacts
+      - name: Upload notarized artifact
         uses: actions/upload-artifact@v4
         with:
           if-no-files-found: error
-          name: ${{ env.ARTIFACT_NAME }}
+          name: ${{ env.ARTIFACT_PREFIX }}${{ env.ARTIFACT_SUFFIX }}
           path: ${{ env.DIST_DIR }}
 
   create-release:
@@ -266,8 +274,9 @@ jobs:
       - name: Download artifact
         uses: actions/download-artifact@v4
         with:
-          name: ${{ env.ARTIFACT_NAME }}
+          merge-multiple: true
           path: ${{ env.DIST_DIR }}
+          pattern: ${{ env.ARTIFACT_PREFIX }}*
 
       - name: Identify Prerelease
         # This is a workaround while waiting for create-release action