fix releases index channel 2.2 security (#10009)

Co-authored-by: Ondrej Smid <[email protected]>

Author: ondrejsmid

release-notes/releases-index.json

@@ -126,7 +126,7 @@
       "channel-version": "2.2",
       "latest-release": "2.2.8",
       "latest-release-date": "2019-11-19",
-      "security": true,
+      "security": false,
       "latest-runtime": "2.2.8",
       "latest-sdk": "2.2.207",
       "product": ".NET Core",