Bump up version to v2.6.0

Signed-off-by: Daijiro Fukuda <fukuda@clear-code.com>

Author: daipom

NEWS.md

@@ -6,6 +6,12 @@
 
 * adds `partial_metadata_format` to support Docker 20.10 journald log driver improvements [moby/moby#41407](https://github.com/moby/moby/pull/41407) 
 
+## v2.6.0
+
+### Improvements
+
+* Support `buffer_limit_size`, `buffer_overflow_method` to change behavior when buffer overflow. See #68
+
 ## v2.3.0
 
 ### Improvements

fluent-plugin-concat.gemspec

@@ -4,7 +4,7 @@ $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 
 Gem::Specification.new do |spec|
   spec.name          = "fluent-plugin-concat"
-  spec.version       = "2.5.0"
+  spec.version       = "2.6.0"
   spec.authors       = ["Kenji Okimoto"]
   spec.email         = ["okimoto@clear-code.com"]