ci(nightly): run the version step in bash on Windows

The Windows build job defaults to PowerShell, where the bash-style
"${NIGHTLY_VERSION}" expands to an empty string and the version script
rejects it, failing the master build before any artifact exists.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.github/workflows/build-and-make.yaml

@@ -495,6 +495,9 @@ jobs:
               # comes from the nightly-version job so every job of this run
               # builds the same version.
               if: needs.nightly-version.outputs.version != ''
+              # Windows runners default to PowerShell, where "${NIGHTLY_VERSION}"
+              # expands to nothing and the script rejects the empty version.
+              shell: bash
               env:
                   NIGHTLY_VERSION: ${{ needs.nightly-version.outputs.version }}
               run: node tools/release/nightly-version.mjs --apply --version "${NIGHTLY_VERSION}"