Use `buildVersion` metadata tag to include build-specific info

[briandk]

buildVersion String - The build version. Maps to the CFBundleVersion on macOS, and FileVersion metadata property on Windows. Defaults to the version. If TRAVIS_BUILD_NUMBER or APPVEYOR_BUILD_NUMBER or CIRCLE_BUILD_NUM or BUILD_NUMBER or bamboo.buildNumber env defined, it will be used as a build version (version.build_number).

Source: https://www.electron.build/configuration/configuration

Just use -c.extraMetadata.version=YOUR_VAL

Source: electron-userland/electron-builder#2232 (comment)