switch to gcc11

Author: sdcb

.github/workflows/opencv.yml

@@ -109,7 +109,9 @@ jobs:
           script=$(
             cat <<'EOS'
             yum install -y epel-release
-            yum install -y gcc cmake3 gcc gcc-c++
+            yum install -y gcc cmake3 devtoolset-11-gcc devtoolset-11-gcc-c++
+            source /opt/rh/devtoolset-11/enable
+            echo "source /opt/rh/devtoolset-11/enable" > /etc/profile.d/enable-gcc11.sh
             ln -s /usr/bin/cmake3 /usr/bin/cmake
         EOS
           )