REL: 4.0.0

## What's new

pypdf==4.0.0 is a big milestone forward:

* We finally have a layout-mode text extraction.
  This enables users who want to detect / extract tables
  with heuristics to give it a try.
* We deprecated a lot of the old PyPDF2 API that was either
  not following PEP8 naming styles or was not using a
  property. Users comming from PyPDF2 might want to switch
  first to pypdf<4.0.0 to get helpful error messages
  that show the new API in their speicific cases.

A big 'Thank you!' the the whole pypdf community for your
work. Thanks to you, pypdf is better than ever.

Kudos to @shartzog who added the layout-mode with his first
contribution!

### Deprecations (DEP)
-  Drop Python 3.6 support (#2369) by @MartinThoma
-  Remove deprecated code (#2367) by @MartinThoma
-  Remove deprecated XMP properties (#2386) by @stefan6419846

### New Features (ENH)
-  Add "layout" mode for text extraction (#2388) by @shartzog
-  Add Jupyter Notebook integration for PdfReader (#2375) by @MartinThoma
-  Improve/rewrite PDF permission retrieval (#2400) by @stefan6419846

### Bug Fixes (BUG)
-  PdfWriter.add_uri was setting the wrong type (#2406) by @pmiller66
-  Add support for GBK2K cmaps (#2385) by @stefan6419846

### Documentation (DOC)
-  Add pmiller66 for #2406 as a contributor by @MartinThoma
-  Add missing expand parameter (#2393) by @Atomnp
-  Resolve build warnings (#2380) by @stefan6419846
-  Fix testing prerequisites (#2381) by @stefan6419846
-  Improve formatting of contributors page (#2383) by @stefan6419846
-  Add Tobeabellwether as a contributor for #2341 by @MartinThoma

### Developer Experience (DEV)
-  Make dependabot aware of our PR prefixes (#2415) by @stefan6419846
-  Fail on Sphinx issues (#2405) by @stefan6419846
-  Move title check to own workflow (#2384) by @MasterOdin
-  Write to temporary files instead of the working directory (#2379) by @stefan6419846
-  Ensure that the PR titles have the correct format (#2378) by @stefan6419846

### Maintenance (MAINT)
-  Complete FileSpecificationDictionaryEntries constants (#2416) by @MartinThoma
-  Return None instead of -1 when page is not attached (#2376) by @MartinThoma
-  Replace warning with logging.error (#2377) by @MartinThoma

### Testing (TST)
-  Add missing pytest.mark.samples annotations (#2412) by @kitterma
-  Correctly close temporary files (#2396) by @stefan6419846
-  Fix  side effect #2379 (#2395) by @pubpub-zz
-  Add test for layout extraction mode (#2390) by @MartinThoma

### Code Style (STY)
-  Use the UserAccessPermissions enum (#2398) by @MartinThoma
-  Run black (#2370) by @MartinThoma

[Full Changelog](3.17.4...4.0.0)

CHANGELOG.md

@@ -1,5 +1,28 @@
 # CHANGELOG
 
+## Version 4.0.0, 2024-01-19
+
+### Deprecations (DEP)
+-  Drop Python 3.6 support (#2369)
+-  Remove deprecated code (#2367)
+-  Remove deprecated XMP properties (#2386)
+
+### New Features (ENH)
+-  Add "layout" mode for text extraction (#2388)
+-  Add Jupyter Notebook integration for PdfReader (#2375)
+-  Improve/rewrite PDF permission retrieval (#2400)
+
+### Bug Fixes (BUG)
+-  PdfWriter.add_uri was setting the wrong type (#2406)
+-  Add support for GBK2K cmaps (#2385)
+
+### Maintenance (MAINT)
+-  Return None instead of -1 when page is not attached (#2376)
+-  Complete FileSpecificationDictionaryEntries constants (#2416)
+-  Replace warning with logging.error (#2377)
+
+[Full Changelog](https://github.com/py-pdf/pypdf/compare/3.17.4...4.0.0)
+
 ## Version 3.17.4, 2023-12-24
 
 ### Bug Fixes (BUG)

pypdf/_version.py

@@ -1 +1 @@
-__version__ = "3.17.4"
+__version__ = "4.0.0"