ci : update windows artifact uploads steps

This commit updates the windows job steps to use the built-in zip
feature of the actions/upload-artifact action. This simplifies the jobs
and also avoids the issue of zipping twice. This also modifies
windows-blas which was updated previously but to now make the zip achive
have an `Release` directory in it. Currently the files are all directly
in the archive which I think might be surprising to most developers.

Author: danbev

.github/workflows/build.yml

@@ -604,19 +604,14 @@ jobs:
           name: ggml_cpu_${{ matrix.arch }}.dll
           path: build/bin/${{ matrix.build }}/ggml-cpu.dll
 
-      - name: Pack bin artifacts
-        shell: pwsh
-        run: |
-              Compress-Archive -Path "build/bin/${{ matrix.build }}" -DestinationPath "whisper-bin-${{ matrix.arch }}.zip"
-
       - name: Upload binaries
         if: matrix.sdl2 == 'ON' && ${{ (github.event_name == 'push' && github.ref == 'refs/heads/master') ||
                 github.event.inputs.create_release == 'true' ||
                 github.event.inputs.pre_release_tag != '' }}
         uses: actions/upload-artifact@v4
         with:
           name: whisper-bin-${{ matrix.arch }}.zip
-          path: whisper-bin-${{ matrix.arch }}.zip
+          path: "build/bin/${{ matrix.build }}"
 
   windows-blas:
     if: ${{ github.event_name == 'push' || github.event_name == 'pull_request' ||
@@ -699,7 +694,7 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: whisper-blas-bin-${{ matrix.arch }}.zip
-          path: "build/bin/${{ matrix.build }}/**"
+          path: "build/bin/${{ matrix.build }}"
 
   windows-cublas:
     if: ${{ github.event_name == 'push' || github.event_name == 'pull_request' ||
@@ -889,19 +884,14 @@ jobs:
         if: matrix.sdl2 == 'ON'
         run: copy "$env:SDL2_DIR/../lib/${{ matrix.arch }}/SDL2.dll" build/bin/${{ matrix.build }}
 
-      - name: Pack bin artifacts
-        shell: pwsh
-        run: |
-              Compress-Archive -Path "build/bin/${{ matrix.build }}" -DestinationPath "whisper-cublas-${{ matrix.cuda-toolkit }}-bin-${{ matrix.arch }}.zip"
-
       - name: Upload binaries
         if: ${{ (github.event_name == 'push' && github.ref == 'refs/heads/master') ||
                 github.event.inputs.create_release == 'true' ||
                 github.event.inputs.pre_release_tag != '' }}
         uses: actions/upload-artifact@v4
         with:
           name: whisper-cublas-${{ matrix.cuda-toolkit }}-bin-${{ matrix.arch }}.zip
-          path: whisper-cublas-${{ matrix.cuda-toolkit }}-bin-${{ matrix.arch }}.zip
+          path: "build/bin/${{ matrix.build }}"
 
   emscripten:
     if: ${{ github.event_name == 'push' || github.event_name == 'pull_request' ||