flow: NPM version check failure

The plugin tries to verify the version of npm, but uses node for this. That is failing of course.

[INFO] --- vaadin-maven-plugin:17.0.0:prepare-frontend (default) @ appointments ---
[INFO] Couldn't find npm. Installing Node and NPM to /home/local-admin/.vaadin.
[INFO] Installing node version v12.16.0
[INFO] Downloading https://nodejs.org/dist/v12.16.0/node-v12.16.0-linux-x64.tar.gz to /home/local-admin/.vaadin/node-v12.16.0-linux-x64.tar.gz
[INFO] No proxies configured
[INFO] No proxy was configured, downloading directly
[INFO] Unpacking /home/local-admin/.vaadin/node-v12.16.0-linux-x64.tar.gz into /home/local-admin/.vaadin/node/tmp
[INFO] Copying node binary from /home/local-admin/.vaadin/node/tmp/node-v12.16.0-linux-x64/bin/node to /home/local-admin/.vaadin/node/node
[INFO] Extracting NPM
[INFO] Local node installation successful.
[WARNING] Error checking if npm is new enough
com.vaadin.flow.server.frontend.FrontendUtils$UnknownVersionException: Unable to detect version of npm. Using command /home/local-admin/.vaadin/node/node --no-update-notifier --no-audit --version
    at com.vaadin.flow.server.frontend.FrontendUtils.getVersion (FrontendUtils.java:886)

BTW: The current Node LTS is 12.18.3