Modify run.sh to use redirects rather than screen

[solvaholic]

Modify run.sh to use redirects, rather than screen, to create plan and log files.

Description

Currently run.sh relies on screen to write command exit status in its output file. This pull request replaces that with shell redirects.

Motivation and Context

screen on a given Actions runner may not write command exit status in its output file.

Fixes #92

How Has This Been Tested?

Tested the redirects manually, locally, running octodns sync in shells of Docker containers; Pushed the code to issue92 branch and ran it in triggered workflows using solvaholic/octodns-sync@issue92.

See also #92 (comment)

To-Do List

• Resolve the issue reported in Script exiting with non-zero exist status even if successful #92
  Redirect output rather than capture it with screen
• Mention Script exiting with non-zero exist status even if successful #92 on stdout, for folks expecting to see log output
  Echo comments to stdout, link to the issue
• Expose octodns sync output as an Action output
  Set it in script and update action.yml and README.md
• Update CHANGELOG.md
  Add a new entry for this pull request, Modify run.sh to use redirects rather than screen #93
• Raise set-output is being deprecated #94 to handle deprecation of set-output

[solvaholic]

Timely, as this project uses set-output and already needs work on its outputs:
https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

[solvaholic]

From #92 (comment):

Somewhat related .. while looking for context I see this project used to use tee (#23) and after moving to screen (#24) it was still/again possible for this action to silently fail (#40).

[solvaholic]

I ran 3a27125 successfully in solvahol/dns. I'd like to also confirm the outputs work, and see how the Action behaves when octodns sync fails.

@laszlof if you're still running @issue92, or would like to check it again, please let me know how it goes.

[laszlof]

@solvaholic I'll give this a shot in the coming days. I've been out of town this week. Thanks for the fixes!