Bump to 8.1.2 final

CHANGES.rst

@@ -1,5 +1,5 @@
-Release 8.1.2 (in development)
-==============================
+Release 8.1.2 (released Oct 12, 2024)
+=====================================
 
 Bugs fixed
 ----------

sphinx/__init__.py

@@ -30,11 +30,11 @@ warnings.filterwarnings(
 #:
 #: .. versionadded:: 1.2
 #:    Before version 1.2, check the string ``sphinx.__version__``.
-version_info = (8, 1, 2, 'beta', 0)
+version_info = (8, 1, 2, 'final', 0)
 
 package_dir = os.path.abspath(os.path.dirname(__file__))
 
-_in_development = True
+_in_development = False
 if _in_development:
     # Only import subprocess if needed
     import subprocess