Custom shortcut for switching input sources in macOS High Sierra

I need to remap "Select the previous input source" shortcut in macOS High Sierra 10.13.

I recently installed fresh macOS High Sierra removing my previous OS and I found that there is no option to change default shortcut from Ctrl+Space to something else.

I used to use macOS Sierra and I managed to set this shortcut to Cmd ⌘+Space. I didn't use any third party software for changing it, however I don't remember how exactly I changed it.

Is there any way to reset it to some custom shortcut? Ideally I'd remap it to Caps Lock which is never used in practice, but Cmd ⌘+Space would also be fine.

UPDATE: After some research I found that it is already possible to remap switching to and from ABC to Caps Lock. There is an option in System Preferences > Keyboard > Input Sources:

But the question is still open since this allows only to switch to and from ABC, but having three input sources you are not able to switch to the third one.

Go to System Preferences > Keyboard > Shortcuts > Input Sources:

Then double-click the shortcut listed to the right and enter your preference.

References:
macOS Sierra: Use global keyboard shortcuts (Published Date: Mar 28, 2017)
Mac keyboard shortcuts (Published Date: Jun 11, 2017)
OS X El Capitan: Use input sources to type in other languages (Published Date: Sep 15, 2017)
macOS Sierra: If a keyboard shortcut doesn’t work (Published Date: Mar 28, 2017)