chore: include a date

Author: imconnorngl

client-brand.mdx

@@ -16,7 +16,7 @@ The client brand is sent as a comma-delimited list of identifiers. For example:
 The first identifier is always `lunarclient:<VERSION>`, where `<VERSION>` is the Lunar Client build that the user is running. Additional identifiers may be appended to indicate other mod loaders or relevant context. See the next section for info about the version format.
 
 <Callout type="info" emoji="ℹ️">
-  **Format Change:** Previously, the client brand was sent as a single string (`lunarclient:<VERSION>`). This change aligns the Lunar Client brand format with other modern mod loaders such as Fabric and Forge, improving compatibility with mods and plugins that rely on client branding to detect mod loaders.
+  **Format Change:** As of 1st December 2025, the client brand was sent as a single string (`lunarclient:<VERSION>`). This change aligns the Lunar Client brand format with other modern mod loaders such as Fabric and Forge, improving compatibility with mods and plugins that rely on client branding to detect mod loaders.
 </Callout>
 
 ## Version Format