CI: test make artifacts on every PR

A preparation toward fixing issue 4241

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

Author: AkihiroSuda

.github/workflows/release.yml

@@ -5,6 +5,9 @@ on:
     tags:
     - 'v*'
     - 'test-action-release-*'
+  pull_request:
+    paths-ignore:
+    - '**.md'
 
 env:
   GOTOOLCHAIN: local
@@ -53,6 +56,7 @@ jobs:
       with:
         subject-path: _output/*
     - name: "Create release"
+      if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v')
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |