add comment for working-directory var

Author: davegarthsimpson

.github/workflows/build.yml

@@ -72,10 +72,11 @@ env:
         # and the companion needs.select-targets.outputs.merge-channel-files property (output values always have string
         # type).
         mergeable-channel-file: 'false'
-        # as this runs on a self hosted runner, we need to override the default working directory,
+        # as this runs on a self hosted runner, we need to avoid building with the default working directory path,
         # otherwise paths in the build job will be too long for `light.exe`
+        # we use the below as a Symbolic  as just changing the wd will break our checkout action
+        # as a work around. see: https://github.com/actions/checkout/issues/197
         working-directory: 'C:\a'
-        relative-working-directory: '../../../../a'
       artifacts:
         - path: '*Windows_64bit.exe'
           name: Windows_X86-64_interactive_installer