This reusable action follows Semantic Versioning, v2.0.0.
A new patch version is automatically tagged when a group of commits is pushed to the main branch;
for example, when a group that comprises a pull request is merged.
Alternatively, a new patch version is tagged for each commit in the group that has a message title prefixed with fix.
For example, a commit with the following message title would tag a new patch version when it is pushed to the main branch:
fix: a bug fix
A new minor version is tagged for each commit in the group that has a message title prefixed with feat.
For example, a commit with the following message title would tag a new minor version when it is pushed to the main branch:
feat: a new feature
A new major version is tagged for each commit in the group that has BREAKING CHANGE in its message body.
For example, a commit with the following message body would tag a new major version:
Remove a function
BREAKING CHANGE: Removing a function is not backwards-compatible.
Whilst there are other prefixes besides fix and feat, they do not tag new versions.