Cannot update heroku-cli to version 7.* on Windows 10

[robert-skarzycki]

Do you want to request a feature or report a bug?

It looks like a bug.

What is the current behavior?

When I get fresh installation for Windows x64 from https://cli-assets.heroku.com/heroku-x64.exe - despite information inside installer popup that it is going to intall some 7.* version of heroku-cli, finally 6.16.17 version is installed. That's what I see after installation:

λ heroku --version
 !    heroku-cli: update available from 6.16.17 to 6.99.0-ec9edad
heroku-cli/6.16.17 (win32-x64) node-v10.15.0

Previously I had same with Node 8., then I upgraded Node to 10. but nothing changes.
When I tried to run heroku update it told me:

λ heroku update
 !    Update CLI with `npm update -g heroku-cli`

However, running this seems to change nothing:

C:\Users\Robert
λ npm update -g heroku-cli

C:\Users\Robert
λ heroku --version
 !    heroku-cli: update available from 6.16.17 to 6.99.0-ec9edad
heroku-cli/6.16.17 (win32-x64) node-v10.15.0

P.S. I've also tried to clean installation, with removing %LOCALAPPDATA%/heroku folder, but it didn't help.
P.P.S. My OS is Windows 10, I'm using cmder as a console.

What is the expected behavior?

I expect to have an ability to either directly install 7.* version of heroku-cli or upgrade from exisitng one. I is related to #1181 - I can't upgrade.