I wanted to know- Colloportus seems to be a spell that locks a door/something.
Alohomora seems to be a spell that unlocks a door/something.
So can Alohomora break Colloportus?
Absolutely, we see this at least as early as The Order of the Phoenix, where Hermione's Colloportus is undone by Alohomora.
'Colloportus!' gasped Hermione and the door sealed itself with an odd squelching noise.
They were almost there when Harry heard something large and heavy collide with the door Hermione had charmed shut.
'Stand aside!' said a rough voice. 'Alohomora!'
As the door flew open, Harry, Hermione and Neville dived under desks.
Harry Potter and the Order of the Phoenix - p.695 - Bloomsbury - Chapter 35, Beyond the Veil
So this was firmly established in the original series as a key limitation of Colloportus /power of Alohomora and isn't an innovation of The Cursed Child. (Just for the benefit of those who might be wondering about The Cursed Child's tendency to reimagine earlier events and information).
Yes. As shown in Cursed Child,
DELPHI: Potter. Colloportus!
ALBUS opens both doors with his wand.
ALBUS: Alohomora! Alohomora!
There we see Delphi using Colloportus, and Albus breaking it with Alohomora.
Yes, you can check on Wikia.
Colloportus is a charm which makes a door lock. It can be redone by Alohomora.