More remainings of yarn removed.

Author: thet

Makefile

@@ -48,7 +48,7 @@ bundle: clean-dist bundle-pre install
 
 .PHONY: serve
 serve: install
-	$(YARN) run start
+	$(PNPM) run start
 
 
 .PHONY: docs

README.md

@@ -180,9 +180,9 @@ After developing you might want to run `pnpm unlink "PACKAGE-NAME"` to unlink th
 
 For more information see:
 
-- https://classic.yarnpkg.com/en/docs/cli/link/
-- https://classic.yarnpkg.com/en/docs/cli/unlink
-- https://docs.npmjs.com/cli/v7/commands/npm-link
+- https://pnpm.io/cli/link
+- https://pnpm.io/cli/unlink
+- https://docs.npmjs.com/cli/v11/commands/npm-link
 
 **Please note:**: Make sure to unlink and reinstall development pacakges before building a production bundle.
 In doubt, remove the node_modules directory and re-install.