release: update publish vsix node version (aws#5085)

problem:
- the lowest node version that can be used for open vsx is node 18. We currently use node 16 which fails the release process

solution:
- use node 20

Author: jpinkney-aws

buildspec/release/60publish.yml

@@ -7,7 +7,7 @@ version: 0.2
 phases:
     install:
         runtime-versions:
-            nodejs: 16
+            nodejs: 20
         commands:
             - apt-get update
             - apt-get install -y libsecret-1-dev