net-im/gotosocial: Upgrade to 0.13.0 SpiderSloth

Explicitly use go 1.21.

Changelogs since 0.11.0:

• https://github.com/superseriousbusiness/gotosocial/releases/tag/v0.13.0
• https://github.com/superseriousbusiness/gotosocial/releases/tag/v0.12.2
• https://github.com/superseriousbusiness/gotosocial/releases/tag/v0.12.1
• https://github.com/superseriousbusiness/gotosocial/releases/tag/v0.11.1

PR: 275827