docs: add release-notes

Author: Euler-B

docker/btcd/Dockerfile

@@ -1,7 +1,6 @@
 # If you change this please also update GO_VERSION in Makefile (then run
 # `make lint` to see where else it needs to be updated as well).
-ARG GO_VERSION=1.25.5
-FROM golang:${GO_VERSION}-alpine AS builder
+FROM 1.25.5-alpine AS builder
 
 LABEL maintainer="Olaoluwa Osuntokun <laolu@lightning.engineering>"
 

docs/release-notes/release-notes-0.21.0.md

@@ -234,6 +234,12 @@
 
 ## Tooling and Documentation
 
+* [Overhauled Docker documentation and environment](https://github.com/lightningnetwork/lnd/pull/10461)
+  to modernize the developer onboarding flow. Key updates include migrating 
+  to Docker Compose V2, updating base images (btcd v0.25.0, Go 1.25.5), 
+  and transitioning the documentation to focus on a more reliable "Simnet" 
+  workflow while removing obsolete faucet references.
+
 # Contributors (Alphabetical Order)
 
 * bitromortac