update docs

docs/outdated_mode.md

@@ -12,12 +12,16 @@ The `outdated_mode` input option has three possible values:
 - `pr_base`: The branch-deploy Action will consider your branch (that you are deploying) to be out-of-date if it is behind the branch that your pull request is merging into.
 - `default_branch`: The branch-deploy Action will consider your branch (that you are deploying) to be out-of-date if it is behind the default|stable branch (i.e `main`). The `default_branch` is determined by the value you have set for the `stable_branch` input option. By default, the value of the `stable_branch` input option is `main`.
 
+### How the `outdated_mode` input option works with the `update_branch` input option
+
 If your branch is determined to be out-of-date, the branch-deploy Action will not deploy your branch. What happens next is determined by the value of the `update_branch` input option. Here are the three possible values for the `update_branch` input option and how they will operate:
 
 - `warn`: The branch-deploy Action will leave a comment on your pull request indicating that your branch is out-of-date and that you should update it before it can be deployed.
 - `force`: The branch-deploy Action will attempt to update your branch by merging the latest commits into your branch for you. You will need to re-run the deployment command after the branch-deploy Action has attempted to update your branch.
 - `disabled`: The branch-deploy Action will allow you to deploy your branch even if it is out-of-date. (dangerous)
 
+It should be noted that if you are using the `force` value for the `update_branch` input option, the branch-deploy Action will only attempt to update your branch with the target base branch of the pull request. This means that if your target base branch is something other than the default|stable branch, the branch-deploy Action will only attempt to update your branch with the latest commits from the target base branch. You will still be warned about your branch being out-of-date with the default|stable branch but it will not try to update your branch with the latest commits from the default|stable branch due to the complexity and potential risk involved with such a merge. You will need to manually update your branch with the latest commits from the default|stable branch if you want to deploy your branch and that is the case.
+
 ## About the `outdated_mode` input option
 
 The `outdated_mode` input option is useful when you want to ensure that the branch-deploy Action only deploys branches that are up-to-date. This is especially useful when you have a large team of developers working on a project and you want to ensure that commits are not rolled back accidentally when you are deploying a branch. For the sake of availability and deployment confidence, this input option is set to `strict` by default. This will ensure that your branch is up-to-date with the latest commits from both the default|stable branch and the branch that your pull request is merging into.