update-common: add missing semicolon
Quoting this page[1] on the differences in sed implementations:
function lists (multiple function calls enclosed in {...}), be sure
to also terminate the last function, before the closing }, with ;.
We need to terminate every function in a function list with a newline (or semicolon).
[1]https://riptutorial.com/sed/topic/9436/bsd-macos-sed-vs--gnu-sed-vs--the-posix-sed-specification
Cc: @ken-martin