bump action from Node12 to Node16

🚨 Node 12 has an end of life on April 30, 2022.

The GitHub Actions workflow gives the following annotation while running the action:

> Node.js 12 actions are deprecated. For more information see: github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12.

This PR updates the default runtime to [node16](https://github.blog/changelog/2021-12-10-github-actions-github-hosted-runners-now-run-node-js-16-by-default/), rather then node12. 

This is supported on all Actions Runners v2.285.0 or later.

Signed-off-by: Enes <[email protected]>

Author: devenes

action.yml

@@ -13,5 +13,5 @@ outputs:
   sarifFile:
     description: A file path to a SARIF results file.
 runs:
-  using: 'node12'
-  main: 'lib/action.js'
+  using: 'node16'
+  main: 'lib/action.js'