Add automated update workflow.

.github/workflows/update_manifest.yml

@@ -0,0 +1,64 @@
+name: Check for updates
+
+on:
+  schedule: # for scheduling to work this file must be in the default branch
+  - cron: "0 * * * *" # run every hour
+  workflow_dispatch: # can be manually dispatched under GitHub's "Actions" tab
+
+env:
+# email sets "github-actions[bot]" as commit author, see https://github.community/t/github-actions-bot-email-address/17204/6
+  GIT_USER_NAME: github-actions[bot]
+  GIT_USER_EMAIL: 41898282+github-actions[bot]@users.noreply.github.com
+  FLATPAK_ID: com.artemis_rgb.Artemis
+
+jobs:
+  flatpak-external-data-checker:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        branch: [ main ] # list all branches to check
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ matrix.branch }}
+
+      - name: Check for Flatpak source updates via Flatpak External Data Checker
+        uses: docker://ghcr.io/flathub/flatpak-external-data-checker:latest
+        with:
+          args: --edit-only ${{ env.FLATPAK_ID }}.yml
+
+      - name: Attempt to update the Artemis git sources
+        run: |
+          ./.github/scripts/update-manifest.py
+
+      - name: Verify if git was updated
+        id: is-updated
+        run: |
+          git status -s -uno
+          [ -z "$(git status -s -uno)" ] || echo "updated=true" >> $GITHUB_OUTPUT
+
+      - name: Generate dotnet sources
+        if: steps.is-updated.outputs.updated
+        run: |
+          ./generate-sources.sh
+
+      - name: Reset Flatpak manifest to pre-modified state
+        run: |
+          git checkout -- ${FLATPAK_ID}.yml
+
+      - name: Run the Artemis git source updates again
+        run: |
+          ./.github/scripts/update-manifest.py
+
+      - name: Run Flatpak External Data Checker again and Open PR
+        uses: docker://ghcr.io/flathub/flatpak-external-data-checker:latest
+        env:
+          GIT_AUTHOR_NAME: Flatpak External Data Checker
+          GIT_COMMITTER_NAME: Flatpak External Data Checker
+          GIT_AUTHOR_EMAIL: ${{ env.GIT_USER_NAME }}
+          GIT_COMMITTER_EMAIL: ${{ env.GIT_USER_EMAIL }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          args: --update --never-fork ${{ env.FLATPAK_ID }}.yml