workflows/release-binaries: Add missing output variable

[kwk]

LGTM. But just to be sure, I assume, that this refers to echo "upload=$upload" >> $GITHUB_OUTPUT in D143535, correct?

[tstellar]

In D148734#4281400, @kwk wrote:

LGTM. But just to be sure, I assume, that this refers to echo "upload=$upload" >> $GITHUB_OUTPUT in D143535, correct?

Correct, yes.

.github/workflows/release-binaries.yml

prepare:
     runs-on: ubuntu-22.04
     if: github.repository == 'llvm/llvm-project'
     outputs:
       release-version: ${{ steps.validate-tag.outputs.release-version }}
       release: ${{ steps.validate-tag.outputs.release }}
       build-dir: ${{ steps.validate-tag.outputs.build-dir }}
       rc-flags: ${{ steps.validate-tag.outputs.rc-flags }}
       ref: ${{ steps.validate-tag.outputs.ref }}
+      upload: ${{ steps.validate-tag.outputs.upload }}
 
     steps:
     - name: Checkout LLVM
       uses: actions/checkout@v3
 
     - name: Validate and parse tag
       id: validate-tag
       # In order for the test-release.sh script to run correctly, the LLVM