docs(release): update README.md

Longhorn 8997

Signed-off-by: Derek Su <[email protected]>

README.md

@@ -40,6 +40,7 @@ https://github.com/longhorn/longhorn/releases
 
 | Release   | Latest Version | Stable Versions       | Release Note                                                   | Important Note                                              | Supported          |
 |-----------|-----------------|----------------------|----------------------------------------------------------------|-------------------------------------------------------------| -------------------|
+| **1.7***  | 1.7.0           |  | [🔗](https://github.com/longhorn/longhorn/releases/tag/v1.7.0) | [🔗](https://longhorn.io/docs/1.7.0/important-notes) | ✅                 |
 | **1.6***  | 1.6.2           | 1.6.2, 1.6.1 | [🔗](https://github.com/longhorn/longhorn/releases/tag/v1.6.2) | [🔗](https://longhorn.io/docs/1.6.2/deploy/important-notes) | ✅                 |
 | **1.5***  | 1.5.5           | 1.5.5, 1.5.4, 1.5.3 | [🔗](https://github.com/longhorn/longhorn/releases/tag/v1.5.5) | [🔗](https://longhorn.io/docs/1.5.5/deploy/important-notes) | ✅                 |
 | 1.4       | 1.4.4           | 1.4.4, 1.4.3, 1.4.2, 1.4.1 | [🔗](https://github.com/longhorn/longhorn/releases/tag/v1.4.4) | [🔗](https://longhorn.io/docs/1.4.4/deploy/important-notes) |                    |