Update existing ubuntu.sources file to specify the architecture to fix package resolution issues

Author: Exanite

sources/SDL/Native/build-linux-arm.sh

@@ -10,6 +10,7 @@ if [[ ! -z ${GITHUB_ACTIONS+x} ]]; then
     # Enable ports repository
     sudo apt-get update
     sudo apt install lsb-release
+    sudo sed -i "/^Signed-By: /a Architectures: amd64" /etc/apt/sources.list.d/ubuntu.sources
     sudo tee /etc/apt/sources.list.d/ubuntu-ports.sources <<EOF
 Types: deb
 URIs: http://ports.ubuntu.com/ubuntu-ports/

sources/SDL/Native/build-linux-arm64.sh

@@ -10,6 +10,7 @@ if [[ ! -z ${GITHUB_ACTIONS+x} ]]; then
     # Enable ports repository
     sudo apt-get update
     sudo apt install lsb-release
+    sudo sed -i "/^Signed-By: /a Architectures: amd64" /etc/apt/sources.list.d/ubuntu.sources
     sudo tee /etc/apt/sources.list.d/ubuntu-ports.sources <<EOF
 Types: deb
 URIs: http://ports.ubuntu.com/ubuntu-ports/