Add a CI build for double precision

Author: beomki-yeo

.github/workflows/builds.yml

@@ -39,6 +39,11 @@ jobs:
             cxx_standard: "20"
             options: -DTRACCC_BUILD_CUDA=TRUE -DCMAKE_CUDA_FLAGS="-std=c++20"
             run_tests: false
+          - name: CUDA-double
+            container: ghcr.io/acts-project/ubuntu2404_cuda:56
+            cxx_standard: "20"
+            options: -DTRACCC_CUSTOM_SCALARTYPE=double -DDETRAY_CUSTOM_SCALARTYPE=double -DTRACCC_BUILD_CUDA=TRUE -DCMAKE_CUDA_FLAGS="-std=c++20"
+            run_tests: false
           - name: SYCL
             container: ghcr.io/acts-project/ubuntu2404_oneapi:56
             cxx_standard: "20"