Correct minimum macOS version for Arduino IDE 2.x

Compatibility with macOS Mojave was lost in Arduino IDE 2.3.0. The minimum compatible macOS version is now Catalina.

The minimum requirements information in the installation tutorial must be updated to reflect this change.

Author: per1234

Diff for: content/software/ide-v2/tutorials/getting-started/01.ide-v2-downloading-and-installing/ide-v2-downloading-and-installing.md

@@ -17,7 +17,7 @@ You can easily download the editor from the [Arduino Software page](https://www.
 
 - **Windows** - Win 10 and newer, 64 bits
 - **Linux** - 64 bits
-- **Mac OS X** - Version 10.14: "Mojave" or newer, 64 bits
+- **Mac OS X** - Version 10.15: "Catalina" or newer, 64 bits
 
 ### The Arduino IDE 2