feat: preserve fixed upstream versions with fork suffixes

README.md

@@ -19,7 +19,16 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version: '1.23'
-      - uses: https://gitea.com/your-user/gitbump@master
+      - uses: https://lab.zlymeda.dynu.net/actions/gitbump@master
+```
+
+For a fixed base version with an incrementing fork suffix:
+
+```yaml
+- uses: https://lab.zlymeda.dynu.net/actions/gitbump@master
+  with:
+    bump: suffix
+    suffix: meda
 ```
 
 ### Inputs
@@ -27,7 +36,8 @@ jobs:
 | Input | Description | Default |
 |-------|-------------|---------|
 | `dry-run` | Show what would be done without making changes | `false` |
-| `bump` | Force specific bump type (`major`, `minor`, or `patch`) | |
+| `bump` | Force specific bump type (`major`, `minor`, `patch`, or `suffix`) | |
+| `suffix` | Suffix label used when creating the first suffix | |
 | `prefix` | Version prefix | `v` |
 | `no-push` | Create tag but don't push to remote | `false` |
 | `major-patterns` | Comma-separated list for major version bumps | `bump major,breaking change` |