MR to update technical committee details

[Matthew Vernon <matthew@debian.org>]

Hi,

I've just opened an MR to reflect that Sean's term on the technical 
committee has ended, and that I'm the current Chair:
https://salsa.debian.org/webmaster-team/webwml/-/merge_requests/1021

I hope that's sufficient, but if you need anything else from me, please 
let me know (and CC me, please, I'm not subscribed to this list).

Thanks,

Matthew