message: chore: create a temporary .dockerignore during the docker build step
  This speeds up the 'docker build' step, as it reduces the amount of 'build
  context' that needs to be sent to docker.
diff: @@ -65,7 +65,9 @@ fi
  IMAGE_ID="etcher-build-$ARGV_ARCHITECTURE"
  +cp "$ARGV_SOURCE_CODE_DIRECTORY/.gitignore" "$ARGV_SOURCE_CODE_DIRECTORY/.dockerignore"
  docker build -f "$DOCKERFILE" -t "$IMAGE_ID" "$ARGV_SOURCE_CODE_DIRECTORY"
  +rm -f "$ARGV_SOURCE_CODE_DIRECTORY/.dockerignore"
  # Docker complaints with: ". includes invalid characters for a local
  # volume name, only [a-zA-Z0-9][a-zA-Z0-9_.-] are allowed" otherwise
  