You really need to start doing a quick search on the internet for answers. Like I've said multiple times - Linux Mint is Ubuntu based and the answers are there.

Google "Skype for Linux Ubuntu" or "Manually updating packages Ubuntu"

You can also open your terminal and use "sudo apt update && sudo apt upgrade" to update all packages on your system however I am not 100% sure if Skype for Linux updates automatically - It has been upwards of 10 years since I've used Skype.

Question, how did you get installed originally?

You have 3 options

1) install/update Skype as a snap:
sudo apt install snapd
sudo snap install skype --classic

2) add skype ppa to the system and install/update via apt

3) download and update manually:
wget https://go.skype.com/skypeforlinux-64.deb
sudo dpkg -i skypeforlinux-64.deb

skype still receives updates on Linux?
If you don't have to update then why bother?

I haven't used skype for a number of years now, but when I did it was always better on Linux than Windows, simply because the awful updates that were foisted on Windows users weren't available for Linux users.