Prepare for possible release

autorelease/config.json

@@ -1,5 +1,5 @@
 {
   "beta": false,
   "major": false,
-  "humble": null
+  "humble": true
 }

docs/devel/changelog_staging.md

@@ -4,7 +4,11 @@
 <!-- List character: dash (-) -->
 
 # Changelog for next release
+*This is expected to be the last release of the v4 series.*
 - `PdfPage.get_objects()`: Don't register pageobjects as children, because they don't need to be closed by the caller when part of a page. This avoids excessive caching of weakrefs that are not cleaned up with the object they refer to.
+- Fixed another dotted filepath blunder in the `extract-images` CLI. (The `PdfImage.extract()` API is not affected this time.)
+- Fixed installation with reference bindings (`PDFIUM_BINDINGS=reference`) by adding a missing `mkdir` call. (In older versions, this can be worked around by unpacking the sdist and creating the missing directory manually before installation.)
 - Autorelease: Swapped default condition for minor/patch update, as pypdfium2 changes are likely more API-significant than pdfium updates. Added ability for manual override.
 - Fixed conda packaging: It is now required to explicitly specify `-c defaults` with `--override-channels`, presumably due to an upstream change.
 - Bumped workflows to Python 3.12.
+- Updated docs on licensing.