I see that after 45.0.0 was released and announced on the blog, there are 4 patches released to npm. There is no changelog of this anywhere, neither on the repo’s changelog.md file nor on the blog.
sdk version is just one number, there is only SDK 45, there is no SDK 45.0.1, 45.0.2, so there is one changelog for sdk45.
If you want to see changes between expo@45.0.1 and expo@45.0.2, every package in expo repo have a changelog e.g. expo package is here expo/CHANGELOG.md at sdk-45 · expo/expo · GitHub but most of the packages should have those changes on the main branch also