Please bump vulnerable Expat to 2.2.1

[hartwork]

Please excuse my posting style.

Vulnerable copies found at:
https://github.com/gobolinux/Recipes/tree/master/revisions/Expat

Expat 2.2.1 change log:
https://github.com/libexpat/libexpat/blob/master/expat/Changes

Commits that you may want on top:

• libexpat/libexpat@602e6c7
• libexpat/libexpat@e5e25fa

Best, Sebastian

[hishamhm]

Updated, thank you!