CAMEL-11500: for PnP to work we need Yarn 13+

Yarn 13+ patches `resolve` module to resolve from PnP[1].

[1] yarnpkg/yarn#6816

Author: zregvart

.dockerignore

@@ -0,0 +1 @@
+**/*

Dockerfile

@@ -0,0 +1,13 @@
+FROM node:lts-stretch
+
+ENV YARN_VERSION 1.13.0
+
+RUN set -ex \
+  && curl -fsSLO --compressed "https://yarnpkg.com/downloads/$YARN_VERSION/yarn-v$YARN_VERSION.tar.gz" \
+  && curl -fsSLO --compressed "https://yarnpkg.com/downloads/$YARN_VERSION/yarn-v$YARN_VERSION.tar.gz.asc" \
+  && gpg --batch --verify yarn-v$YARN_VERSION.tar.gz.asc yarn-v$YARN_VERSION.tar.gz \
+  && mkdir -p /opt \
+  && tar -xzf yarn-v$YARN_VERSION.tar.gz -C /opt/ \
+  && ln -fs /opt/yarn-v$YARN_VERSION/bin/yarn /usr/local/bin/yarn \
+  && ln -fs /opt/yarn-v$YARN_VERSION/bin/yarnpkg /usr/local/bin/yarnpkg \
+&& rm yarn-v$YARN_VERSION.tar.gz.asc yarn-v$YARN_VERSION.tar.gz

Jenkinsfile

@@ -17,7 +17,6 @@
  * under the License.
  */
 def NODE = 'git-websites'
-def NODE_IMAGE = 'circleci/node:11-browsers'
 
 pipeline {
     agent {
@@ -42,9 +41,9 @@ pipeline {
     stages {
         stage('Theme') {
             agent {
-                docker {
+                dockerfile {
+                    dir 'camel-website'
                     label "$NODE"
-                    image "$NODE_IMAGE"
                     reuseNode true
                 }
             }
@@ -57,9 +56,9 @@ pipeline {
 
         stage('Website') {
             agent {
-                docker {
+                dockerfile {
+                    dir 'camel-website'
                     label "$NODE"
-                    image "$NODE_IMAGE"
                     reuseNode true
                 }
             }