Please add the following to the upgrading instructions in the wiki page in the section Upgrading from Pattern Lab 1.X to 2.X:

• in the file 00-meta/_00-head.mustache replace {% pattern-lab-head %} with {{{ patternLabHead }}}
• in the file 00-meta/_01-foot.mustache replace {% pattern-lab-foot %} with {{{ patternLabFoot }}}

It took me almost 1 hour reading the source-code to find out that this change was needed for the upgrade.