chore: get back to work after 2.8.1

[skip ci]

Author: rwgk

include/pybind11/detail/common.h

@@ -10,12 +10,12 @@
 #pragma once
 
 #define PYBIND11_VERSION_MAJOR 2
-#define PYBIND11_VERSION_MINOR 8
-#define PYBIND11_VERSION_PATCH 1
+#define PYBIND11_VERSION_MINOR 9
+#define PYBIND11_VERSION_PATCH 0.dev1
 
 // Similar to Python's convention: https://docs.python.org/3/c-api/apiabiversion.html
 // Additional convention: 0xD = dev
-#define PYBIND11_VERSION_HEX 0x02080100
+#define PYBIND11_VERSION_HEX 0x020900D1
 
 #define PYBIND11_NAMESPACE_BEGIN(name) namespace name {
 #define PYBIND11_NAMESPACE_END(name) }

pybind11/_version.py

@@ -8,5 +8,5 @@ def _to_int(s):
         return s
 
 
-__version__ = "2.8.1"
+__version__ = "2.9.0.dev1"
 version_info = tuple(_to_int(s) for s in __version__.split("."))