Fix CUDA CI build failures (#824)

.pipelines/ci.yml

@@ -587,7 +587,7 @@ stages:
 
       - task: UsePythonVersion@0
         inputs:
-          versionSpec: '3.x'
+          versionSpec: '3.12'
           disableDownloadFromRegistry: true
           addToPath: true
           architecture: 'x64'

.pipelines/ci_optional.yml

@@ -170,7 +170,7 @@ stages:
 
       - task: UsePythonVersion@0
         inputs:
-          versionSpec: '3.x'
+          versionSpec: '3.12'
           disableDownloadFromRegistry: true
           addToPath: true
           architecture: 'x64'

cmake/externals/json.cmake

@@ -1,6 +1,6 @@
 FetchContent_Declare(nlohmann_json
-  GIT_REPOSITORY https://github.com/nlohmann/json.git
-  GIT_TAG v3.10.5
+  URL       https://codeload.github.com/nlohmann/json/zip/refs/tags/v3.10.5
+  URL_HASH  SHA1=f257f8dc27c5b8c085dc887b40cddd18ae1f725c
   SOURCE_SUBDIR not_set
   )