Use the latest docker container for tfsec

[owenrumney]

tfsec has moved from liamg/tfsec docker hub to tfsec/tfsec

[yi2020]

Good catch, thank you @owenrumney . We now need to re-run the tests with this container. Do you want to do it, or shall we merge this PR and I'll open a new one with the execution results?

Basically what you need to do is:

1. Clear up the tfsec results that are in the repo with find . -name "tfsec_results.txt" -exec rm {} \;.
2. Run the run_all_tools.sh script.
3. See if there are any cases where tfsec didn't catch the issue before, and does now, and update the results_summary.json to reflect that.
4. Run the generate_readme_tables.py script to regenerate the tables, and replace them in the README.md file.

If you see a better way to doing this, let's improve the process. This is a collaborative effort.

[owenrumney]

Hey @yi2020 - if you're happy to just merge it and it'll get picked up on the next execution. I don't have a CLOUDRAIL_API_KEY so doesn't look like I'll get the full results.

[yi2020]

No problem, I'll take care of it.