revert switch to yarn 2

.gitignore

@@ -1,5 +1 @@
-.yarn/unplugged
+/node_modules/
-.yarn/build-state.yml
-.yarn/cache
-*.log
-.pnp.*

.yarnrc.yml

@@ -1,4 +0,0 @@
-yarnPath: ".yarn/releases/yarn-berry.js"
-npmScopes:
-  scode:
-    npmRegistryServer: "https://npm.scode.ovh"

Jenkinsfile

@@ -16,7 +16,6 @@ pipeline {
                 script {
                     currentBuild.displayName = env.VERSION
                 }
-				sh 'yarn'
                 sh 'yarn ci ${VERSION}'
             }
         }

package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "lint": "eslint .",
 	"test": "echo \"no test\"",
-    "ci": "yarn node jenkins.js"
+    "ci": "yarn --frozen-lockfile && node jenkins.js"
   },
   "repository": {
     "type": "git",