fix: use --snapshot flag for GoReleaser dry-run mode (#40)

* fix: use --snapshot flag for GoReleaser dry-run mode

When running via workflow_dispatch in dry-run mode, GoReleaser failed
because the tag does not exist on the commit. Use --snapshot to skip
git state validation and build without publishing. Also skip Docker
setup/login steps during dry-run.

* refactor: simplify GoReleaser args by computing snapshot flag in resolve step

Move --snapshot flag computation into the resolve_tag step output
to eliminate duplicated args in the ternary expression.

Author: skyoo2003

.github/workflows/release.yml

@@ -33,30 +33,36 @@ jobs:
       with:
         go-version-file: go.mod
         cache-dependency-path: go.sum
-    - name: Set up Docker Buildx
-      uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4
-    - name: Login to GitHub Container Registry
-      uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4
-      with:
-        registry: ghcr.io
-        username: ${{ github.actor }}
-        password: ${{ secrets.GITHUB_TOKEN }}
     - name: Resolve tag
       id: resolve_tag
-      run: echo "tag=${{ github.event.inputs.tag || github.ref_name }}" >> "$GITHUB_OUTPUT"
+      run: |
+        echo "tag=${{ github.event.inputs.tag || github.ref_name }}" >> "$GITHUB_OUTPUT"
+        if [[ "${{ github.event.inputs.dry_run }}" == "true" ]]; then
+          echo "extra_flags=--snapshot" >> "$GITHUB_OUTPUT"
+        fi
     - name: Verify changie release notes exist
       run: |
         if [ ! -f "changes/${{ steps.resolve_tag.outputs.tag }}.md" ]; then
           echo "::error::Changie fragment changes/${{ steps.resolve_tag.outputs.tag }}.md not found."
           echo "::error::Run 'changie batch ${{ steps.resolve_tag.outputs.tag }}' and 'changie merge' before pushing the tag."
           exit 1
         fi
+    - name: Set up Docker Buildx
+      if: ${{ github.event.inputs.dry_run != 'true' }}
+      uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4
+    - name: Login to GitHub Container Registry
+      if: ${{ github.event.inputs.dry_run != 'true' }}
+      uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
     - name: Execute GoReleaser
       uses: goreleaser/goreleaser-action@ec59f474b9834571250b370d4735c50f8e2d1e29  # goreleaser-action v7
       with:
         distribution: goreleaser
         version: "~> v2"
-        args: release --clean --release-notes changes/${{ steps.resolve_tag.outputs.tag }}.md ${{ github.event.inputs.dry_run == 'true' && '--skip-publish' || '' }}
+        args: release --clean ${{ steps.resolve_tag.outputs.extra_flags }} --release-notes changes/${{ steps.resolve_tag.outputs.tag }}.md
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     - name: Upload assets