automation: Update matrix-synapse Docker tag to v1.48.0

This MR contains the following updates:

Package	Update	Change
matrix-synapse	minor	1.47.1 -> 1.48.0

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Release Notes

matrix-org/synapse

v1.48.0

Compare Source

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This release removes support for the long-deprecated trust_identity_server_for_password_resets configuration flag.

This release also fixes some performance issues with some background database updates introduced in Synapse 1.47.0.

No significant changes since 1.48.0rc1.

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