Update for POSIX Shell Matrix SDK

### Project Affected

https://matrix.org/ecosystem/sdks/

### Current Information

*Maturity* *Beta*

### Suggested Correction

*Maturity* *Obsolete*

### Source

https://gitlab.com/matrix-mellifluousness/sdk

### Additional Context

*The parent group is archived. This project and its data are read-only.*

Related to #2542.