Update README.md

Author: bigkevmcd

README.md

@@ -5,13 +5,59 @@ This is a small tool for bumping [SemVer](https://semver.org/) versions in YAML
 **NOTE**: This is a very early version - it works, but it's not particularly
 hardened.
 
-Usage:
+## Usage
 
 ```shell
 $ yaml-versioner increment --filename pkg/versioner/testdata/Chart.yaml --key version --patch=true
 ```
 
+This would update the file `pkg/versioner/testdata/Chart.yaml` as a YAML file, incrementing the [SemVer](https://semver.org/) in the top-level `.version` key, but only incrementing the _patch_ level.
+
+If the file looked like this:
+
+```yaml
+apiVersion: v2
+name: test-controller
+description: A Helm chart for Kubernetes
+type: application
+version: 1.0.1
+appVersion: "1.0.0"
+```
+
+Then it would get changed to look like this:
+
+```yaml
+apiVersion: v2
+name: test-controller
+description: A Helm chart for Kubernetes
+type: application
+version: 1.0.2
+appVersion: "1.0.0"
+```
+With a diff of
+
+```diff
+type: application
+- version: 1.0.1
++ version: 1.0.2
+appVersion: "1.0.0"
+```
+
+## Incrementing the minor version
+
+Incrementing the _minor_ level will result in the patch level being reset to zero.
+
+$ yaml-versioner increment --filename pkg/versioner/testdata/Chart.yaml --key version --minor=true
+
+```diff
+type: application
+- version: 1.0.1
++ version: 1.1.0
+appVersion: "1.0.0"
+```
+
 ## TODO
 
-[ ] Metadata in the CLI
-[ ] Replace rather than increment (set a specific version)
+* [ ] [Pre-release data](https://semver.org/#spec-item-9) in the CLI
+* [ ] [Build metadata](https://semver.org/#spec-item-10) in the CLI
+* [ ] Replace rather than increment (set a specific version) for example, this would allow bumping the `.appVersion` in the YAML above