Install yarn in tidy dockerfile

Author: yotamofek

src/ci/docker/scripts/nodejs.sh

@@ -3,8 +3,13 @@
 set -ex
 
 NODEJS_VERSION=v20.12.2
+YARN_VERSION=1.22.22
 INSTALL_PATH=${1:-/node}
 
 url="https://nodejs.org/dist/${NODEJS_VERSION}/node-${NODEJS_VERSION}-linux-x64.tar.xz"
 curl -sL "$url" | tar -xJ
 mv node-${NODEJS_VERSION}-linux-x64 "${INSTALL_PATH}"
+
+# now, install yarn.
+# we call npm through the node binary, because otherwise npm will expect node to be in the PATH
+"${INSTALL_PATH}/bin/node" "${INSTALL_PATH}/bin/npm" install --global yarn@${YARN_VERSION}