sysutils/immortal: Update to 0.15.0

Changes from 0.14.0 to 0.15.0:

• Added option timestamp when logging, if timestamp set to true it will prefix each line with the current time. In case timestamp is set to false, the stdout from the application will directly be written to the log file.
• Added alias reset for halt.

PR: 221158
Submitted by: Nicolas Embriz <nbari@tequila.io> (maintainer)