fix(ci): use pre-installed MSYS2 to avoid installer download failure on Windows build
Add `release: false` to the msys2/setup-msys2@v2 step so the action
uses the MSYS2 pre-installed on GitHub's windows-latest runner at
C:\msys64 instead of downloading a fresh installer from GitHub Releases.
The old behaviour (release: true, the default) fails when MSYS2 is not
in the Actions tool cache — e.g. on fork PRs or fresh runners — because
the installer download step crashes silently almost immediately. Setting
release: false bypasses the download entirely and relies on the
pre-installed copy that every windows-latest image ships with.
copilot-swe-agent[bot]