Add UDFs for 3.10.1.

Otherwise, we cannot run the test suite on the 3.10.1 tentative ISO.

wiki/src/upgrade/v1/Tails/3.10.1/amd64/stable/upgrades.yml

+---
+build-target: amd64
+channel: stable
+product-name: Tails
+product-version: 3.10.1

wiki/src/upgrade/v1/Tails/3.10.1/amd64/stable/upgrades.yml.pgp

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