Upgrade to Node 14 for Actions (#2928)

Summary:
I believe that matches what we have internally. This has been causing some upgrades to fail.

Pull Request resolved: https://github.com/facebook/flipper/pull/2928

Reviewed By: aigoncharov

Differential Revision: D31324394

Pulled By: passy

fbshipit-source-id: eec38dcc6322e3e8957bbc20bf74d343855be8c0

.github/workflows/nodejs.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [12.x]
+        node-version: [14.x]
         os: ['ubuntu-latest', 'windows-latest', 'macos-latest']
 
     steps: