Yes these instructions don't work as well anymore since we publish SNAPSHOTs in CI. We need to come up with a better solution but there are basically 2 ways to deal with it.
1) Find and delete the SNAPSHOT that was downloaded from the internet. You can do this by going to the artifact cache (see https://get-coursier.io/docs/cache#default-location
for where that is) and doing something `find . -name '3.6-SNAPSHOT'` and nuking every directory that shows up. Then if you compile again it should use the local version
2) Pick some wild version number to publish in chisel3 and use in your project, eg. `4.0`. You'll need to make sure to do a `+publishLocal` in this case because the chisel3-plugin is published for each minor version of Scala and thus if you're using a different version than chisel3 uses by default you'll get errors that it can't find plugin published for the right version.
A tip that's useful for both of these approaches is to run `fullClasspath` in SBT in your project, that will show you what jars it's using.
Sorry for the not great instructions.