github: fix build-appimage

.github/workflows/build-appimage.yml

@@ -18,6 +18,13 @@ jobs:
       - name: Set up CentOS 7 Docker
         run: |
           docker run --rm -v $(pwd):/workspace -w /workspace centos:7 /bin/bash -c "
+            # Update repository URLs to use the vault
+            sed -i 's|^mirrorlist=|#mirrorlist=|g' /etc/yum.repos.d/CentOS-*.repo
+            sed -i 's|^#baseurl=http://mirror.centos.org/centos/\$releasever|baseurl=http://vault.centos.org/7.9.2009|g' /etc/yum.repos.d/CentOS-*.repo
+
+            yum clean all
+            yum makecache
+
             yum install -y epel-release
             yum groupinstall -y 'Development Tools'
             yum install -y gtk3-devel glib2-devel gettext-devel desktop-file-utils \