Allow numbers in custom mnemonic names

[matthdsm]

Bug report

Expected behavior and actual behavior

Currently, no numbers are allowed in custom mnemonic names set with -name

Steps to reproduce the problem

nextflow run hello -name 1234

Program output

Not a valid run name: "1234" -- It must match the pattern ^[a-z](?:[a-z\d]|[-_](?=[a-z\d])){0,79}$

Environment

• Nextflow version: [22.04.5]
• Java version: [openjdk 11.0.13 2021-10-19]
• Operating system: all
• Bash version: GNU bash, version 4.4.20(1)-release (x86_64-pc-linux-gnu)