Comment the nasm requirement

CMake Error at scripts/cmake/vcpkg_find_acquire_program.cmake:619 (message):
  Could not find nasm.  Please install it via your package manager:

      brew install nasm
Call Stack (most recent call first):
  ports/ffmpeg/portfile.cmake:31 (vcpkg_find_acquire_program)
  scripts/ports.cmake:147 (include)


error: building ffmpeg:x64-osx-min1012 failed with: BUILD_FAILED

.github/workflows/build.yml

@@ -113,6 +113,7 @@ jobs:
       run: ${{ matrix.vcpkg_bootstrap }}
       working-directory: ${{ matrix.vcpkg_path }}
 
+    # FFmpeg requires nasm
     - name: "[macOS] Bootstrap vcpkg"
       if: runner.os == 'macOS'
       run: |