Issue when running on VS Code ubuntu 20

[dev-loup]

perl send warnings about deprecated syntax

Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.32), passed through in regex; marked by <-- HERE in m/({ <-- HERE )/ at /usr/local/bin/betty-style line 3916.
Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.32), passed through in regex; marked by <-- HERE in m/({ <-- HERE .*})/ at /usr/local/bin/betty-doc line 2038.