Revert "chore(deps): update yarn to v4 (#930)"

This reverts commit eced300.

Author: lodewiges

.yarn/plugins/@yarnpkg/plugin-interactive-tools.cjs

@@ -1,3 +1,7 @@
 nodeLinker: node-modules
 
-yarnPath: .yarn/releases/yarn-4.6.0.cjs
+plugins:
+  - path: .yarn/plugins/@yarnpkg/plugin-interactive-tools.cjs
+    spec: '@yarnpkg/plugin-interactive-tools'
+
+yarnPath: .yarn/releases/yarn-3.8.7.cjs

.yarn/releases/yarn-3.8.7.cjs

@@ -19,7 +19,7 @@ RUN apt-get update -qq && \
   libyaml-dev
 
 # Add Node, required for asset pipeline.
-RUN curl -sL https://deb.nodesource.com/setup_20.x | bash - && \
+RUN curl -sL https://deb.nodesource.com/setup_16.x | bash - && \
   apt-get install -y nodejs && \
   npm install -q -g yarn
 

.yarn/releases/yarn-4.6.0.cjs

@@ -42,5 +42,5 @@
     "sass-lint": "^1.13.1",
     "webpack-dev-server": "^4.15.2"
   },
-  "packageManager": "yarn@4.6.0"
+  "packageManager": "yarn@3.8.7"
 }