qa: Pin qemu version

The PR test job installs qemu in order to run NBD tests.

The issue is that we're hitting checksum errors with the latest
Qemu choco build (released 1 week ago), for which reason we'll
switch to the previous version.

Signed-off-by: Lucian Petrut <lpetrut@cloudbasesolutions.com>

.github/workflows/pr-tests.yaml

@@ -77,7 +77,7 @@ jobs:
           wnbd-client install-driver --debug
           vstudio\x64\${{ matrix.configuration }}\driver\wnbd.inf
       - name: "Install qemu, used for NBD tests"
-        run: choco install qemu
+        run: choco install qemu --version 2023.4.24 -y
       - name: "Add qemu directory to env PATH"
         run: Add-Content $env:GITHUB_PATH 'C:\Program Files\qemu'
       - name: "Create qcow2 image, used for NBD"