chore: add gh action to update app templates hash

[mndeveci]

Which issue(s) does this change fix?

N/A

Why is this change necessary?

We recently added a configuration file which keeps the latest commit hash from aws/aws-sam-cli-app-templates repositorty. This GH action is updating that hash value in configuration by running it every hour (or manually).

Test run in fork: https://github.com/mndeveci/aws-sam-cli/actions/runs/2223773270
Result PR in fork: mndeveci#3

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jfuss]

Requesting changes just to understand the answer of my following question:

How does this handle if the hash is not changing? It seems like this will still create a PR but not sure what the create pr job actually handles this or not.

[jfuss]

Can you add a comment on what this cron is? I hate trying to read cron.

[mndeveci]

You are right, this is for every hour, let me add that as a comment

[mndeveci]

How does this handle if the hash is not changing? It seems like this will still create a PR but not sure what the create pr job actually handles this or not.

I verified this behavior in the test repositories. If there is no change and workflow is going to exit without creating a PR (https://github.com/mndeveci/mock-cli/runs/6180064552?check_suite_focus=true).

Branch 'update_app_templates_hash' no longer differs from base branch 'develop'
Deleting branch 'update_app_templates_hash'

And if next time this workflow runs with a change, it will create a PR (https://github.com/mndeveci/mock-cli/runs/6180080878?check_suite_focus=true).

[mndeveci]

Test cases;

• updating existing PR
  • https://github.com/mndeveci/mock-cli/actions/runs/2229214637
• no pr when there is no change
  • https://github.com/mndeveci/mock-cli/actions/runs/2229208188
• create new pr
  • https://github.com/mndeveci/mock-cli/runs/6183049267?check_suite_focus=true
• create new pr when branch is deleted
  • https://github.com/mndeveci/mock-cli/runs/6183019758?check_suite_focus=true

[jfuss]

LGTM

[mndeveci]

Updated test cases;

• updating existing PR
  • https://github.com/mndeveci/mock-cli/runs/6184415099?check_suite_focus=true
• no pr when there is no change
  • https://github.com/mndeveci/mock-cli/runs/6184396530?check_suite_focus=true
• create new pr
  • https://github.com/mndeveci/mock-cli/runs/6184406578?check_suite_focus=true
• create new pr when branch is deleted
  • https://github.com/mndeveci/mock-cli/runs/6184427323?check_suite_focus=true