ci: run `goreleaser build` (#5824)

# Description

- run build when on a branch matching RC[0-9]/**, in accordance with contributing.md release guide.

Closes: #5695

.github/workflows/release.yml

@@ -2,6 +2,8 @@ name: "Release"
 
 on:
   push:
+    branches: 
+      - "RC[0-9]/**"
     tags:
       - "v[0-9]+.[0-9]+.[0-9]+" # Push events to matching v*, i.e. v1.0, v20.15.10
 
@@ -19,9 +21,18 @@ jobs:
           go-version: '1.15'
 
       - run: echo https://github.com/tendermint/tendermint/blob/${GITHUB_REF#refs/tags/}/CHANGELOG.md#${GITHUB_REF#refs/tags/} > ../release_notes.md 
+        if: startsWith(github.ref, 'refs/tags/')
 
-      - name: Run GoReleaser
+      - name: Build
         uses: goreleaser/goreleaser-action@v2
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          version: latest
+          args: build --skip-validate   # skip validate skips initial sanity checks in order to be able to fully run
+
+      - name: Release
+        uses: goreleaser/goreleaser-action@v2
+        if: startsWith(github.ref, 'refs/tags/')
         with:
           version: latest
           args: release --rm-dist --release-notes=../release_notes.md

.goreleaser.yml

@@ -28,7 +28,7 @@ release:
   name_template: "{{.Version}} (WARNING: BETA SOFTWARE)"
 
 archives:
-  files:
+  - files:
     - LICENSE
     - README.md
     - UPGRADING.md