updates C++ language level

Jenkinsfile

@@ -55,7 +55,7 @@ pipeline {
                 stage('ubuntu-22.04') {
                     agent {docker { 
                         image 'ubuntu-22.04'
-                        args ' -e CONAN_HOME=/var/jenkins_home/workspace/conan-jammy'
+                        args ' -e CONAN_HOME=/var/jenkins_home/workspace/conan-jammy-cxx20'
                     } }
                     stages {
                         stage('Checkout') { steps { checkout_project() }}
@@ -65,13 +65,13 @@ pipeline {
                 stage('rockylinux8') {
                     agent {docker {
                         image 'rockylinux8'
-                        args ' -e CONAN_HOME=/var/jenkins_home/workspace/conan-rocky8'
+                        args ' -e CONAN_HOME=/var/jenkins_home/workspace/conan-rocky8-cxx20'
                     } }
                     stages {
                         stage('Checkout') { steps { checkout_project() }}
                         stage('Build & test') { steps { build_n_test_project() }}
                     }
-                }
+             qq   }
             }
         }
     }