Update README.md

Updating GHES release version dates

Author: ankneis

README.md

@@ -53,10 +53,10 @@ Some features may be marked with a GHES 3.X label, which indicates that the feat
 **GHES release version dates**:
 | **Version Number** | **Release Quarter** | **Release Notes** |
 |-|-|-|
-| 3.5 | Q2 2022 | [Release Notes](https://docs.github.com/en/enterprise-server@3.5/admin/release-notes) |
-| 3.6 | Q3 2022 | [Release Notes](https://docs.github.com/en/enterprise-server@3.6/admin/release-notes) |
-| 3.7 | Q4 2022 | - |
-| 3.8 | Q1 2023 | - |
+| 3.12 | Q1 2024 | [Release Notes](https://docs.github.com/en/enterprise-server@3.12/admin/release-notes#3.12.0)|
+| 3.13 | Q2 2024 | [Release Notes](https://docs.github.com/en/enterprise-server@3.13/admin/release-notes#3.13.0)|
+| 3.14 | Q3 2024 | [Release Notes](https://docs.github.com/en/enterprise-server@3.14/admin/release-notes) |
+| 3.15 | Q4 2024 | -- |
 
 ## Roadmap stages