build: pin python 3.12 exact for now

Author: spwoodcock

pyproject.toml

@@ -3,7 +3,7 @@ name = "ODM"
 version = "3.6.0"
 description = "A command line toolkit to generate maps, point clouds, 3D models and DEMs from drone, balloon or kite images."
 readme = "README.md"
-requires-python = ">=3.12"
+requires-python = "==3.12"
 dependencies = [
     "appsettings==0.8",
     "beautifulsoup4==4.13.4",