node cache: Don't shell out to yarn to get the version.
node cache: Don't shell out to yarn to get the version.

This can easily be done by just reading the package.json file and
extracting the version value, just like we now do in install-node.

brainwane/zulip,rht/zulip,showell/zulip,eeshangarg/zulip,hackerkid/zulip,tommyip/zulip,kou/zulip,synicalsyntax/zulip,brainwane/zulip,eeshangarg/zulip,rishig/zulip,zulip/zulip,rishig/zulip,rht/zulip,zulip/zulip,synicalsyntax/zulip,brainwane/zulip,kou/zulip,kou/zulip,brainwane/zulip,shubhamdhama/zulip,hackerkid/zulip,tommyip/zulip,punchagan/zulip,shubhamdhama/zulip,punchagan/zulip,dhcrzf/zulip,showell/zulip,tommyip/zulip,andersk/zulip,rishig/zulip,punchagan/zulip,kou/zulip,jackrzhang/zulip,synicalsyntax/zulip,timabbott/zulip,jackrzhang/zulip,zulip/zulip,tommyip/zulip,kou/zulip,andersk/zulip,timabbott/zulip,kou/zulip,zulip/zulip,jackrzhang/zulip,rishig/zulip,jackrzhang/zulip,punchagan/zulip,dhcrzf/zulip,timabbott/zulip,zulip/zulip,showell/zulip,eeshangarg/zulip,jackrzhang/zulip,synicalsyntax/zulip,rht/zulip,jackrzhang/zulip,synicalsyntax/zulip,timabbott/zulip,dhcrzf/zulip,hackerkid/zulip,timabbott/zulip,rht/zulip,showell/zulip,zulip/zulip,hackerkid/zulip,rht/zulip,jackrzhang/zulip,dhcrzf/zulip,eeshangarg/zulip,shubhamdhama/zulip,punchagan/zulip,tommyip/zulip,eeshangarg/zulip,dhcrzf/zulip,rishig/zulip,hackerkid/zulip,punchagan/zulip,andersk/zulip,rht/zulip,tommyip/zulip,rishig/zulip,synicalsyntax/zulip,eeshangarg/zulip,brainwane/zulip,shubhamdhama/zulip,eeshangarg/zulip,andersk/zulip,punchagan/zulip,hackerkid/zulip,timabbott/zulip,dhcrzf/zulip,shubhamdhama/zulip,showell/zulip,brainwane/zulip,timabbott/zulip,andersk/zulip,shubhamdhama/zulip,dhcrzf/zulip,andersk/zulip,showell/zulip,brainwane/zulip,kou/zulip,tommyip/zulip,showell/zulip,zulip/zulip,hackerkid/zulip,shubhamdhama/zulip,synicalsyntax/zulip,rishig/zulip,andersk/zulip,rht/zulip