chore: Update update-constraints docs (#23)

Signed-off-by: Ihar Hrachyshka <ihar.hrachyshka@gmail.com>











**Checklist:**

- [ ] **Commit Message Formatting**: Commit titles and messages follow guidelines in the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/#summary).
- [ ] [Changelog](https://github.com/instructlab/ci-actions/blob/main/CHANGELOG.md) updated with breaking and/or notable changes for the next minor release.
- [ ] Documentation has been added and/or updated, if applicable.
- [ ] Unit tests have been added and/or updated. (If this is not applicable, please provide a justification.)
- [ ] Integration testing has been performed, if applicable

## Description of this Change





Approved-by: courtneypacheco

Approved-by: ktdreyer

Author: mergify[bot]

README.md

@@ -20,6 +20,7 @@ Below is a list of the in-house GitHub actions stored in this repository:
 | [free-disk-space](./actions/free-disk-space/free-disk-space.md) | Used to reclaim disk space on either a GitHub or EC2 runner. | <ul><li>If a CI job tends to fail due to "insufficient disk space"</li><li>If you want to reduce cloud costs by reclaiming disk space instead of increasing your writeable cloud storage to compensate for a bloated EC2 image</li></ul> |
 | [launch-ec2-runner-with-fallback](./actions/launch-ec2-runner-with-fallback/launch-ec2-runner-with-fallback.md) | Used launch an EC2 instance in AWS, either as a spot instance or a dedicated instance. If your preferred availability zone lacks availability for your instance type, "backup" availability zones will be tried. | <ul><li>Insufficient capacity in AWS (i.e., AWS lacks availablility for your desired EC2 instance type in your preferred availability zone)</li><li>Cost savings (i.e., You want to try launching your EC2 runner as a spot instance first)</li></ul> |
 | [validate-notebooks](./actions/launch-ec2-runner-with-fallback/launch-ec2-runner-with-fallback.md) | Used to validate `.ipynb` files | <ul><li>I maintain a collection of `.ipynb` files and run ci jobs to test them. I  would like to quickly verify that the files are formatted correctly before spinning up more complex or expensive CI jobs to test those notebooks.</li></ul>
+| [update-constraints](./actions/update-constraints/update-constraints.md) | Used to update `constraints-dev.txt` file | <ul><li>I pin all project dependencies in CI using `constraints-dev.txt` file. I would like to monitor new dependency releases and periodically post PRs to move pins forward.</li></ul>
 
 ## ❓ How to Use One or More In-House GitHub Actions
 

actions/update-constraints/update-constraints.md

@@ -31,6 +31,17 @@ commands = {posargs}
 allowlist_externals = *
 ```
 
+Each project should also list all input requirements files in the
+`requirements-files.in` file, one file name per line.
+
+For example, the `requirements-files.in` file may look like this:
+
+```
+requirements.txt
+requirements-dev.txt
+docs/requirements.txt
+```
+
 ## How to Call this Action
 
 The action is meant to be executed from a separate workflow file. It's advised
@@ -62,8 +73,7 @@ jobs:
         with:
           repository: instructlab/ci-actions
           path: ci-actions
-          # TODO: update with a tag when the action is released?
-          ref: main
+          ref: v0.2.0
           sparse-checkout: |
             actions/update-constraints