Well, your license gave them permission to pretty much do anything. As nefarious as it may be, it is not illegal. https://github.com/avitorio/outstatic/blob/canary/license.md
It's not really about the law either, it's just a total dick move. They could've approached the OP about being co maintainers, or simply say that it's a forked version with improvements, or whatever. No need to steal credit and impersonate the OP.
We didn’t grow up with a lot of money, so I didn’t get to play with fancy systems until school.
The things that I got in trouble for in school are now the same things that I make a living on; protecting apps from younger versions of me lol.
Some colleagues asked me before “but who would be dumb enough to try and log into a sensitive system?”.
My reply would be a naive 16 year old high schooler who doesn’t realize what they are doing, or the skill set that they may harness.