ci: fix dub tests on Windows

This fixes a pesky failure in vs2019 vc2019x64ninja for d/11 dub:
```
Searching in DUB cache for compatible urld.lib
WARNING: No such cache folder: C:\Users\VssAdministrator\AppData\Local\dub\packages\urld-2.1.1\urld\.dub\build
ERROR: urld@2.1.1 not found
You may try the following command to install the necessary DUB libraries:
dub run --yes dub-build-deep -- urld --arch=x86_64 --compiler=dmd --build=debug
Run-time dependency urld found: NO

test cases\d\11 dub\meson.build:13:11: ERROR: Dependency "urld" not found
```

Follow dub's advice by installing urld in ci/run.ps1 before the testsuite;
we were already doing this for ubuntu, opensuse, and even recommending
it in our docs before now:
* ci/ciimage/ubuntu-rolling/install.sh
* ci/ciimage/opensuse/install.sh
* docs/markdown/Dependencies.md

We also bump to 'ci4' which has newer D added (from the cidata repo).

ci/run.ps1

@@ -50,7 +50,7 @@ function DownloadFile([String] $Source, [String] $Destination) {
 
 if (($env:backend -eq 'ninja') -and ($env:arch -ne 'arm64')) { $dmd = $true } else { $dmd = $false }
 
-DownloadFile -Source https://github.com/mesonbuild/cidata/releases/download/ci3/ci_data.zip -Destination $env:AGENT_WORKFOLDER\ci_data.zip
+DownloadFile -Source https://github.com/mesonbuild/cidata/releases/download/ci4/ci_data.zip -Destination $env:AGENT_WORKFOLDER\ci_data.zip
 echo "Extracting ci_data.zip"
 Expand-Archive $env:AGENT_WORKFOLDER\ci_data.zip -DestinationPath $env:AGENT_WORKFOLDER\ci_data
 & "$env:AGENT_WORKFOLDER\ci_data\install.ps1" -Arch $env:arch -Compiler $env:compiler -Boost $true -DMD $dmd
@@ -87,6 +87,44 @@ if ($env:backend -eq 'ninja') {
   MSBuild /version
 }
 
+# This mirrors the D logic in cidata/build_win32.sh
+if ($dmd) {
+  if ($Arch -eq "x64") {
+    $dmdArch = "x86_64"
+  } else {
+    $dmdArch = "x86_mscoff"
+  }
+
+  $ScriptDir = Split-Path $script:MyInvocation.MyCommand.Path
+  $env:Path = "$ScriptDir;$env:Path"
+  $dmd_bin  = Join-Path $ScriptDir "dmd2\windows\bin"
+  $env:Path = $env:Path + ";" + $dmd_bin
+
+  $i = 1
+  while ($i -le 5) {
+    # Needed for d/11 dub to use the 'urld' library
+    dub run --yes dub-build-deep -- urld --arch=$dmdArch --compiler=dmd --build=debug
+    if ($LastExitCode -eq 0) {
+      break
+    }
+
+    $i = $i + 1
+    Start-Sleep -Seconds 2
+  }
+
+  $i = 1
+  while ($i -le 5) {
+    # XXX: Sometimes (?) we need this older version when the whole testsuite is run
+    dub run --yes dub-build-deep -- urld@2.1.1 --arch=$dmdArch --compiler=dmd --build=debug
+    if ($LastExitCode -eq 0) {
+      break
+    }
+
+    $i = $i + 1
+    Start-Sleep -Seconds 2
+  }
+}
+
 echo ""
 echo "Python version:"
 python --version