Docs: mention Boost::Python retired

CHANGES-3.3

@@ -15,7 +15,11 @@ This release contains contributions from (alphabetically by first name):
  - Anke Boersma
 
 ## Core ##
- - No changes yet
+ - Boost::Python is no longer a dependency, Calamares uses a bundled copy
+   of pybind11 instead. This speeds up compilation and reducese the
+   dependency tree a great deal. You can set `WITH_PYBIND11=OFF` in the
+   build to keep Boost::Python and all the binary-compatibility problems
+   it entails.
 
 ## Modules ##
  - All QML modules now have a Qt6-compatible set of QML files as well. (thanks Anke)

CONTRIBUTING.md

@@ -131,7 +131,7 @@ Main:
 * KDE extra-cmake-modules >= 5.78 (recommended; required for some modules;
   required for some tests)
 * Python >= 3.6 (required for some modules)
-* Boost.Python >= 1.72.0 (required for some modules)
+* Boost.Python >= 1.72.0 (required for some modules if WITH_PYBIND11 is OFF)
 
 Individual modules may have their own requirements;
 these are listed in CMake output.

src/modules/README.md

@@ -334,7 +334,8 @@ description if something went wrong.
 The interface from a Python module to Calamares internals is
 found in the *libcalamares* module. This is not a standard Python
 module, and is only available inside the Calamares "runtime" for
-Python modules (it is implemented through Boost::Python in C++).
+Python modules (it is implemented in C++ and injected into the Python
+environment by Calamares).
 
 A module should start by importing the Calamares internals: