When moving to the new CRT build process, this was missed from the older
build scripts. When building the plugins for Windows, if the files do
not have the `.exe` suffix, boundary fails with errors like the
following:
Error initializing controller: error creating aws host plugin: error fetching host plugin rpc client: exec:
"C:\\Users\\alice\\AppData\\Local\\Temp\\441718622\\boundary-plugin-host-aws": file does not exist
Timothy Messier
