Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `.github/workflows/build-image.yml`:
  Fix erroneous deletion in a previous merge.
- `Gemfile`:
  Conflict caused by glitch-soc-only hCaptcha dependency
- `app/controllers/auth/sessions_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
- `app/controllers/filters_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
- `app/serializers/rest/status_serializer.rb`:
  Minor conflict due to glitch-soc having an extra `local_only` property

.github/workflows/build-image.yml

@@ -0,0 +1,43 @@
+name: Build container image
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - 'main'
+    tags:
+      - '*'
+  pull_request:
+    paths:
+      - .github/workflows/build-image.yml
+      - Dockerfile
+jobs:
+  build-image:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: docker/setup-qemu-action@v2
+      - uses: docker/setup-buildx-action@v2
+      - uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+        if: github.event_name != 'pull_request'
+      - uses: docker/metadata-action@v4
+        id: meta
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/mastodon
+          flavor: |
+            latest=auto
+          tags: |
+            type=edge,branch=main
+            type=match,pattern=v(.*),group=0
+            type=ref,event=pr
+      - uses: docker/build-push-action@v3
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          cache-from: type=registry,ref=ghcr.io/${{ github.repository_owner }}/mastodon:latest
+          cache-to: type=inline