fix(windows): correct path to output file in publish step for fv keyboards

[mcdurdin]

Addresses a build warning. The path for the output file corresponds to the publish step for Keyman.

Fixes: #12636

@keymanapp-test-bot skip

[keymanapp-test-bot[bot]]

User Test Results

Test specification and instructions

User tests are not required

Test Artifacts

• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[keyman-server]

Changes in this pull request will be available for download in Keyman version 18.0.138-alpha