The latest edition (7th ed, 2015) actually uses 4.5 as well. AFAIK OpenGL hasn't changed too much since 3.3, certainly not to the point of being irrelevant for learning.
Maybe 3.3 and 4.5 aren't actually that different, but they certainly feel very different to program.
I have moved on however towards the DX12/Vulkan like APIs. Currently using WebGPU as a stop-gap, it gives me an easy to use API (compared to Vulkan) with strengths of those explicit APIs. I think in 2021, even if people are writing OpenGL engines, they are already using the "RenderPipeline/RenderPass" abstraction to fit the new APIs better.
No idea how it looks like in 2021.