docs: add integration flutter 2.8 PR link

wssgcg1213 · wssgcg1213 · commit 8edbdc92e015 · 2022-04-07T19:33:26.000+08:00
diff --git a/kraken/CHANGELOG.md b/kraken/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 **Breaking Changes**
 
-+ Update flutter requirement to 2.8.x
++ Update flutter requirement to 2.8.x https://github.com/openkraken/kraken/pull/1298
 
 **Bug Fixed**
 
