From 07c1d10212720e22de499429d8254ddd0fb08d9d Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Fri, 14 May 2021 16:16:23 +0900
Subject: [PATCH] ci: avoid clang-9 + C++20 because it lacks <=>

And the operator<=> is used in the (GNU-) standard library
implementation installed by default.
Note: consider using libc++ library
---
 .github/workflows/main.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 04ab80b..874886b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -59,6 +59,7 @@ jobs:
             - {compiler: '6.0', standard: '20'}
             - {compiler: '7',   standard: '20'}
             - {compiler: '8',   standard: '20'}
+            - {compiler: '9',   standard: '20'}
     steps:
       - name: Checkout
         uses: actions/checkout@v2