Ethereum doesn't pegged with bitcoin to get a pump. Recently there was a very big news has come and that makes ethereum gets a big pump and the news was about the launch of ethereum 2.0 test net in the next month. In mt opinion any pump that happened have been getting affected by the news.
Try to look at the bitcoin and ethereum charts on the market today. almost looks the same doesn't it? I believe an update can make a pump. but in the current events, I'm sure it's because of bitcoin.