add changelog with a note on release workflow (#4890)

closes: #4881

CHANGELOG.md

@@ -0,0 +1,63 @@
+# Changelog
+
+See [RELEASE](./RELEASE.md) for workflow instructions.
+
+## UNRELEASED
+
+### Upgrade information
+
+Legacy discovery protocol was removed in [4836](https://github.com/spacemeshos/go-spacemesh/pull/4836).
+Config option and flag `p2p-disable-legacy-discovery` is noop, and will be completely removed in future versions. 
+
+### Highlights
+
+### Features
+
+* [#4845](https://github.com/spacemeshos/go-spacemesh/pull/4845) API to fetche opened connections.
+
+> grpcurl -plaintext 127.0.0.1:9093 spacemesh.v1.AdminService.PeerInfoStream
+
+```json
+{
+  "id": "12D3KooWEcgADBR4zHirw7YAt6nUtCNhbPWkB2fnHAemnG5cGf2n",
+  "connections": [
+    {
+      "address": "/ip4/46.4.81.145/tcp/5001",
+      "uptime": "1359.186975782s",
+      "outbound": true
+    }
+  ]
+}
+{
+  "id": "12D3KooWHK5m83sNj2eNMJMGAngcS9gBja27ho83t79Q2CD4iRjQ",
+  "connections": [
+    {
+      "address": "/ip4/34.86.244.124/tcp/5000",
+      "uptime": "1108.414456262s",
+      "outbound": true
+    }
+  ],
+  "tags": [
+    "bootnode"
+  ]
+}
+```
+
+* [4795](https://github.com/spacemeshos/go-spacemesh/pull/4795) p2p: add ip4/ip6 blocklists
+
+Doesn't affect direct peers. In order to disable:
+
+
+```json
+{
+  "p2p": {
+    "ip4-blocklist": [],
+    "ip6-blocklist": []
+  }
+}
+```
+
+### Improvements
+
+* [#4882](https://github.com/spacemeshos/go-spacemesh/pull/4882) Increase cache size and parametrize datastore.
+* [#4887](https://github.com/spacemeshos/go-spacemesh/pull/4887) Fixed crashes on API call.

RELEASE.md

@@ -0,0 +1,25 @@
+# Release
+
+## Releasing a major version.
+
+Rename UNRELEASED to a concrete <version> and create a PR with commit: Release <version>. 
+Branch name should match the <version> set in CHANGELOG. 
+Additionally tag that same commit with 0 as a patch version (if branch is v1.1 - tag is v1.1.0).
+
+## Releasing a minor version.
+
+### Latest
+
+Rename UNRELEASED to a concrete <version>. If previous major was v1.1.0, new version will
+be v1.1.1. 
+Commit changes, create pr, and create a tag.
+Rebase released branch onto develop.
+
+This is a simplified workflow to avoid cherry-picks and maintaining changelog in several branches.
+
+### Previous
+
+Cherry-pick selected commits to major release branch.
+Copy selected commits to CHANGELOG.md.
+Rename UNRELEASED to a concrete <version>.
+Commit changes, and create a tag.