Added `--user-agent` to build script usage msg.
Added `--user-agent` to build script usage msg.

sammuelyee/validator,sammuelyee/validator,validator/validator,takenspc/validator,sammuelyee/validator,YOTOV-LIMITED/validator,tripu/validator,sammuelyee/validator,takenspc/validator,sammuelyee/validator,tripu/validator,YOTOV-LIMITED/validator,validator/validator,tripu/validator,YOTOV-LIMITED/validator,tripu/validator,takenspc/validator,validator/validator,YOTOV-LIMITED/validator,takenspc/validator,YOTOV-LIMITED/validator,validator/validator,takenspc/validator,validator/validator,tripu/validator