cabal dies when creating pkg registration file (Windows)

**Describe the bug**
Building on Windows (using cabal-3.0) I am getting the following error:
```
cabal v2-build Win32-network
...
Creating package registration file:
\\vboxsrv\iohk\ouroboros-network\dist-newstyle\tmp\package-registration--6792\pkgConf
\\vboxsrv\iohk\ouroboros-network\dist-newstyle\tmp\package-registration--6792\: openBinaryTempFileWithDefaultPermissions: does not exist (No such file or directory)
CallStack (from HasCallStack):
die', called at .\\Distribution\\Client\\ProjectOrchestration.hs:1035:55 in main:Distribution.Client.ProjectOrchestration
cabal.exe: Failed to build Win32-network-0.1.0.0-inplace. The failure occurred
during the final install step.
```

**Expected behavior**
A clear and concise description of what you expected to happen.

**System information**
- Operating system: Windows 10
- `cabal-3.0`, `ghc-8.6.5`

**Additional context**
Add any other context about the problem here.

Start at Distribution/Client/ProjectOrchestration.hs:1035 and reproduce cabal v2-build Win32-network on Windows 10 with cabal-3.0 and GHC 8.6.5. Trace the package registration file creation and the reported temporary-path failure; done means the build completes without this error.

Written by the indexing model from the issue text.