ci: bump microsoft/setup-msbuild from v1 to v2

The main benefit: The new version uses a node.js version that is not yet deprecated. Links: - [Release notes](https://github.com/microsoft/setup-msbuild/releases) - [Changelog](https://github.com/microsoft/setup-msbuild/blob/main/building-release.md) - [Commits](https://github.com/microsoft/setup-msbuild/compare/v1...v2) This patch was originally by GitHub's Dependabot, but I cannot attribute that bot properly because it has no dedicated email address. Probably because it hasn't reached legal age yet, or something. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>