Colossal Order have released the first post-launch patch for Cities: Skylines today, taking the game to version 1.0.6b and addressing one or two bugs. The announcement of this patch said it may take a couple of hours to be distributed across Steam, but by now that should have happened.
If your copy of Cities: Skylines hasn’t auto-updated to 1.0.6b, you can try restarting Steam or verifying the game cache through your library (right-click on Cities: Skylines, go to properties, find the local files tab and then select the verify option.)
The lower right corner of the game’s main menu lists the version number, so you can tell if you have the latest one that way too.
Having not played the game, I don’t know how crucial things like “road upgrade tool now works between two-way and one-way roads and right mouse-button changes direction of one-way roads” are. That sounds fairly handy, though.
There’s now a Film Grain slider in the graphics options, and a chirper volume slider in the audio menu. Someone in the comments below the patch notes personally thanks Colossal Order for that latter addition, so they’ve definitely done something right there.
Parks also appear to have been slightly lowered in power: “nerfed parks decreasing commercial demand.”
You can read the complete changelog right here.