docs: add 0.15.4 release note

Signed-off-by: evenyag <[email protected]>

Author: evenyag

blog/release-0-15-4.md

@@ -0,0 +1,24 @@
+---
+keywords: [release, GreptimeDB, changelog, v0.15.4]
+description: GreptimeDB v0.15.4 Changelog
+date: 2025-08-04
+---
+
+# v0.15.4
+
+Release date: August 04, 2025
+
+### 🚀 Features
+* feat: support `__schema__` and `__database__` in Prom Remote Read by [@waynexia](https://github.com/waynexia) in [#6610](https://github.com/GreptimeTeam/greptimedb/pull/6610)
+* feat: `absent` function in PromQL by [@waynexia](https://github.com/waynexia) in [#6618](https://github.com/GreptimeTeam/greptimedb/pull/6618)
+* feat: schema/database support for label_values by [@sunng87](https://github.com/sunng87) in [#6631](https://github.com/GreptimeTeam/greptimedb/pull/6631)
+* feat: Add option to limit the files reading simultaneously by [@evenyag](https://github.com/evenyag) in [#6635](https://github.com/GreptimeTeam/greptimedb/pull/6635)
+
+### 🐛 Bug Fixes
+* fix: only return the __name__ label when there is one by [@waynexia](https://github.com/waynexia) in [#6629](https://github.com/GreptimeTeam/greptimedb/pull/6629)
+
+## All Contributors
+
+We would like to thank the following contributors from the GreptimeDB community:
+
+[@evenyag](https://github.com/evenyag), [@sunng87](https://github.com/sunng87), [@waynexia](https://github.com/waynexia)