scripts/calcurse-upgrade.sh: Fix POSIX compatibility
scripts/calcurse-upgrade.sh: Fix POSIX compatibility

* Split sed(1) one-liners into multiple lines. POSIX sed(1) doesn't
  allow separating functions by semicolons.

* Escape a newline in the awk(1) script. POSIX awk(1) only allows
  non-escaped line breaks in specific contexts.

Signed-off-by: Lukas Fleischer <af90e31281d8305af43dc616c5aaca3c7165f8a7@cryptocrack.de>

lfos/calcurse,lfos/calcurse,lfos/calcurse