chore: set 0.7.3 release date

Author: shpaass

changelog.txt

@@ -12,7 +12,7 @@
 //         Changes to the code that do not affect the behavior of the program.
 ----------------------------------------------------------------------------------------------------------------------
 Version 0.7.3
-Date: soon
+Date: July 21st 2024
     Features:
         - Use modern Direct3D on Windows.
         - Add the option to specify how many beacons, with what modules, should be applied on a per-building-type