mail-client/betterbird-bin: add 140.12.0, drop 140.2.1

[nado]

• 140.2.1 distfile returned 404 so I dropped it
• removed executable bit on .desktop file, fixing pkgcheck warning

Closes following bugs:

• https://bugs.gentoo.org/967038
• https://bugs.gentoo.org/972901

[nado]

@justin025 could I get a quick review?

[justin025]

Looks good to me, apologies that I haven't been able to maintain my guru packages as life has gotten in the way. One recommendation, format your git message as follows to automatically close bugs on the gentoo bugtracker:

Closes: https://bugs.gentoo.org/967038

If you are using betterbird regularly feel free to pick up the maintainer status

[nado]

Thanks for taking a look, no worry about the lack of time, I'll wait a bit before picking up the maintainer status because I'm not sure life won't do the same to me. I'll pick it up if I find myself opening another bump PR in the future though.

How should I format multiple bug links in the commit message? Comma separated, or maybe only space separated?

Closes: https://bugs.gentoo.org/967038, https://bugs.gentoo.org/972901

Edit: nvm, found the format (one Closes by line) by looking in the git log