appveyor: replace choco with pinned/hashed direct download for docker

To avoid chocolatey as a dependency, to add hash verification, and to
control version bumps. The latter is also the slight downside, it needs
to be bumped manually.

Note: With tests disabled docker-cli isn't actually used in CI at the
moment.

Cherry-picked from #1892

Closes #1894

appveyor.sh

@@ -34,3 +34,11 @@ cmake -B _builds \
   -DRUN_SSHD_TESTS=OFF \
   ${CMAKE_GENERATE:-}
 cmake --build _builds --config "${CMAKE_CONFIGURATION}" --parallel 2
+
+# Install docker-cli for tests
+if [ "${SKIP_CTEST:-}" != 'yes' ]; then
+  cd /c && mkdir my-docker && cd my-docker
+  curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 120 --retry 3 --retry-connrefused \
+    "https://download.docker.com/win/static/stable/x86_64/docker-${DOCKER_CLI_VERSION}.zip" --output pkg.bin
+  sha256sum pkg.bin && sha256sum pkg.bin | grep -qwF -- "${DOCKER_CLI_SHA256}" && 7z x -y pkg.bin >/dev/null && rm -f pkg.bin && ls -l && docker --version
+fi

appveyor.yml

@@ -34,6 +34,8 @@ environment:
   CMAKE_VERSION: 3.18.4
   CMAKE_SHA256: a932bc0c8ee79f1003204466c525b38a840424d4ae29f9e5fb88959116f2407d
   DO_NOT_TRACK: '1'
+  DOCKER_CLI_VERSION: 29.4.1
+  DOCKER_CLI_SHA256: 927cb16737c6b7916db15ce31789c0864cf86264a56f2655bae41faa25628d5b
   FIXTURE_XFER_COUNT: 35020
   SKIP_CTEST: 'yes'  # Connection to test server has been failing consistently since 2024-08-29
 
@@ -102,7 +104,7 @@ matrix:
   fast_finish: true
 
 install:
-  - ps: $env:PATH = "C:/my-cmake/bin;$env:PATH"
+  - ps: $env:PATH = "C:/my-cmake/bin;C:/my-docker/docker;$env:PATH"
   # prepare local SSH server for reverse tunneling from GitHub Actions hosting our docker container
   - ps: |
       $env:OPENSSH_SERVER_PORT = Get-Random -Minimum 2000 -Maximum 2300
@@ -115,7 +117,6 @@ build_script:
 test_script:
   - ps: |
       if($env:SKIP_CTEST -ne 'yes' -and $env:CMAKE_GENERATE -notlike '*ARM64*') {
-        appveyor-retry choco install --yes --no-progress --limit-output --timeout 180 docker-cli
         Write-Host 'Waiting for SSH connection from GitHub Actions' -NoNewline
         $endDate = (Get-Date).AddMinutes(5)
         while((Get-Process -Name 'sshd' -ErrorAction SilentlyContinue).Count -eq 1 -and (Get-Date) -lt $endDate) {