Fix var syntax.

.github/workflows/wheel_linux_x86_64_cu11.yml

@@ -67,18 +67,18 @@ jobs:
 
           CIBW_SKIP: "*-musllinux*"
 
-          CIBW_CONFIG_SETTINGS: --global-option=build_ext --global-option=--define="CMAKE_CXX_COMPILER=$(which g++-${GCC_VERSION});CMAKE_C_COMPILER=$(which gcc-${GCC_VERSION});LIGHTNING_RELEASE_TAG=master"
+          CIBW_CONFIG_SETTINGS: --global-option=build_ext --global-option=--define="CMAKE_CXX_COMPILER=$(which g++-$GCC_VERSION);CMAKE_C_COMPILER=$(which gcc-$GCC_VERSION);LIGHTNING_RELEASE_TAG=master"
 
           # Python build settings
           CIBW_BEFORE_BUILD: |
             cat /etc/yum.conf | sed "s/\[main\]/\[main\]\ntimeout=5/g" > /etc/yum.conf
-            python -m pip install ninja cmake~=3.24.3 auditwheel custatevec-cu${CUDA_VERSION_MAJOR}
+            python -m pip install ninja cmake~=3.24.3 auditwheel custatevec-cu$CUDA_VERSION_MAJOR
             yum clean all -y
             yum install centos-release-scl-rh -y
-            yum install devtoolset-${GCC_VERSION}-gcc-c++ -y
-            source /opt/rh/devtoolset-${GCC_VERSION}/enable -y
+            yum install devtoolset-$GCC_VERSION-gcc-c++ -y
+            source /opt/rh/devtoolset-$GCC_VERSION/enable -y
             yum-config-manager --add-repo https://developer.download.nvidia.com/compute/cuda/repos/rhel7/x86_64/cuda-rhel7.repo -y
-            yum -y install cuda-${CUDA_VERSION_MAJOR}-${CUDA_VERSION_MINOR} git openssh wget
+            yum -y install cuda-$CUDA_VERSION_MAJOR-$CUDA_VERSION_MINOR git openssh wget
 
           # ensure nvcc is available
           CIBW_ENVIRONMENT: |