Add incremental upgrades on the test channel for Tails 4.17

wiki/src/upgrade/v2/Tails/4.16/amd64/test/upgrades.yml

+---
+build-target: amd64
+channel: test
+initial-install-version: '4.16'
+product-name: Tails
+upgrades:
+- details-url: https://tails.boum.org/news/version_4.17/
+  type: major
+  upgrade-paths:
+  - target-files:
+    - sha256: 7491faeb137e933f4387b238ee1656b9559a42de9352a5118770733c7d45f340
+      size: 1184440320
+      url: http://dl.amnesia.boum.org/tails/stable/tails-amd64-4.17/tails-amd64-4.17.iso
+    type: full
+  - target-files:
+    - sha256: d37c76dcaac60f486d5a5e3cd9baf4d7e0e07c85546828502e075f220d66905e
+      size: 353898496
+      url: http://dl.amnesia.boum.org/tails/stable/iuk/v2/Tails_amd64_4.16_to_4.17.iuk
+    type: incremental
+  version: '4.17'

wiki/src/upgrade/v2/Tails/4.16/amd64/test/upgrades.yml.pgp

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