While git is a version control system, and each commit is a new version of your software, these versions are too granular to be meaningful for end-users of your software. In particular because the commit number or hash is seemingly random it is difficult to know if commit abc34ef is more recent than commit 32ff76a [^hash] and if an update is required. To address this, versioning schemes propose assigning meaningful numbers to incremental software versions.

Semantic versioning, often abbreviated as semver, is one of the possible versioning schemes for a project. It provides a systematic way of conveying changes and updates in a software project through a three-part version number, consisting of <Major>.<Minor>.<Patch> components (e.g., 1.2.3).

The key principle behind semantic versioning is to communicate the nature of changes succinctly: a change in the major version indicates incompatible API alterations, a minor version signals backward-compatible feature additions, and a patch version denotes backward-compatible bug fixes.

• Major Version (X.0.0): Increased when incompatible API changes are introduced, meaning that tests that previously passed should now be red. It signifies that existing code relying on your CLI may break. (e.g. you change the option -o to -f) A breaking change also means that the test suite should rewritten.
  You should not have a major version update in the project unless the teachers decide to change something in the API of Pandora.
• Minor Version (1.Y.0): Increased when new features are introduced. (e.g. you implement the feature -o minHumidity) or for backward-compatible improvement. (e.g. you handle American fighters in addition to Russian ones). A minor version is the result of several Commits at least one of them should be a feat: implemented feature X but there should be some test: add some tests for feature X, refactor: create a class to handle Y and docs: add the documentation for the method C::X
• Patch Version (1.0.Z): Raised for backward-compatible bug fixes. It indicates that the code remains compatible, but specific issues have been addressed. (e.g. you have discovered that you have a bug in the Feature avgTemp when the temperature are negative and you fix it.

Learn everything about semver

[^hash]: in reality a commit hash is 40 character long: ca82a6dff817ec66f44342007202690a93763949