Update version string to 2.2.4

Author: rly

core/nwb.file.yaml

@@ -7,7 +7,7 @@ groups:
   attributes:
   - name: nwb_version
     dtype: text
-    value: 2.2.3
+    value: 2.2.4
     doc: File version string. Use semantic versioning, e.g. 1.2.1. This will be the
       name of the format with trailing major, minor and patch numbers.
   datasets:

core/nwb.namespace.yaml

@@ -57,4 +57,4 @@ namespaces:
   - doc: This source module contains neurodata_type for retinotopy data.
     source: nwb.retinotopy.yaml
     title: Retinotopy
-  version: 2.2.3
+  version: 2.2.4

docs/format/source/conf.py

@@ -83,7 +83,7 @@ def setup(app):
 # built documents.
 #
 # The short X.Y version.
-version = 'v2.2.3'
+version = 'v2.2.4'
 # The full version, including alpha/beta/rc tags.
 release = version