ci: add neovim 0.9.4

.github/workflows/ci.yml

@@ -48,6 +48,11 @@ jobs:
     steps:
     - uses: actions/checkout@v3
 
+    - uses: rhysd/action-setup-vim@v1
+      with:
+        neovim: true
+        version: v0.9.4
+
     - name: lua-language-server --check
       run: |
         scripts/luals-check