[Backport] Version bumps from 1.6.0 release (#2965)

This PR backports version bumps from release branch
`release-polkadot-v1.6.0` back to `master` and also moved `prdoc` files
related to the release to the appropriate folder

prdoc/1.6.0/pr_2767.prdoc

@@ -0,0 +1,17 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Extract PartialComponents into type alias `Service`
+
+doc:
+  - audience: Node Dev
+    description: |
+      Simplifies service definitions by extraction of a complicated type into a type alias. No breaking changes.
+
+crates:
+  - name: "sc-service"
+  - name: "node-template"
+  - name: "minimal-node"
+  - name: "cumulus-test-service"
+  - name: "polkadot-parachain-bin"
+  - name: "parachain-template-node"