chore: update go-mp4 to latest commit

[theSuess]

Description

This updates the go mp4 lib to include abema/go-mp4#135 which enables support for probing mp4 files with a co64 box instead of a stco box. This is the case for videos recorded on newer android devices.

Checklist

• I/we have read the GoToSocial contribution guidelines.
• I/we have performed a self-review of added code.
• I/we have written code that is legible and maintainable by others.
• I/we have commented the added code, particularly in hard-to-understand areas.
• I/we have made any necessary changes to documentation.
• I/we have added tests that cover new code.
• I/we have run tests and they pass locally with the changes.
• I/we have run go fmt ./... and golangci-lint run.

[tsmethurst]

Oh thank you, nice :)