CHANGELOG: add a few missing changes

CHANGELOG.md

@@ -20,6 +20,15 @@ v0.23 + 1
   correctly formed, it will give bad results. This is the git approach
   and cuts a significant amount of time when reading the trees.
 
+* Filter registration is now protected against concurrent
+  registration.
+
+* Filenames which are not valid on Windows in an index no longer cause
+  to fail to parse it on that OS.
+
+* Rebases can now be performed purely in-memory, without touching the
+  repository's workdir.
+
 ### API additions
 
 * `git_config_lock()` has been added, which allow for
@@ -35,11 +44,17 @@ v0.23 + 1
 * `git_fetch_options` and `git_push_options` have gained a `custom_headers`
   field to set the extra HTTP header fields to send.
 
-
 * `git_stream_register_tls()` lets you register a callback to be used
   as the constructor for a TLS stream instead of the libgit2 built-in
   one.
 
+* `git_commit_header_field()` allows you to look up a specific header
+  field in a commit.
+
+* `git_commit_extract_signature()` extracts the signature from a
+  commit and gives you both the signature and the signed data so you
+  can verify it.
+
 ### API removals
 
 ### Breaking API changes
@@ -75,6 +90,12 @@ v0.23 + 1
   `GIT_CONFIG_LEVEL_PROGRAMDATA` which represent a rough Windows equivalent
   to the system level configuration.
 
+* `git_rebase_init()` not also takes a merge options.
+
+* The index no longer performs locking itself. This is not something
+  users of the library should have been relying on as it's not part of
+  the concurrency guarantees.
+
 v0.23
 ------