Add slack channel

Signed-off-by: Fiona Liao <[email protected]>

Author: fionaliao

proposals/2025-03-25_otel-delta-temporality-support.md

@@ -13,6 +13,7 @@
 
 * **Other docs or links:**
   * [Original design doc](https://docs.google.com/document/d/15ujTAWK11xXP3D-EuqEWTsxWiAlbBQ5NSMloFyF93Ug/edit?tab=t.0)
+  * [#prometheus-delta-dev](https://cloud-native.slack.com/archives/C08C6CMEUF6) - Slack channel for project
   * Additional context
     * [OpenTelemetry metrics: A guide to Delta vs. Cumulative temporality trade-offs](https://docs.google.com/document/d/1wpsix2VqEIZlgYDM3FJbfhkyFpMq1jNFrJgXgnoBWsU/edit?tab=t.0#heading=h.wwiu0da6ws68)
     * [Musings on delta temporality in Prometheus](https://docs.google.com/document/d/1vMtFKEnkxRiwkr0JvVOrUrNTogVvHlcEWaWgZIqsY7Q/edit?tab=t.0#heading=h.5sybau7waq2q)