The node version is set using the environment variable, NODE_VERSION
6:30:53 AM: Build ready to start
6:30:58 AM: build-image version: ca811f47d4c1cbd1812d1eb6ecb0c977e86d1a1d
6:30:58 AM: build-image tag: v3.3.20
6:30:58 AM: buildbot version: be8ecf2af866e16fa4301cc5c14de2ccbbb21cf4
...
6:31:55 AM: Version '10' not found - try `nvm ls-remote` to browse available versions.
6:31:55 AM: Failed to install node version '10'
6:31:55 AM: Error running command: Build script returned non-zero exit code: 1
6:31:55 AM: Failing build: Failed to build site
6:31:55 AM: Failed during stage 'building site': Build script returned non-zero exit code: 1