message: Update schema for cacheVariables
diff: "type": "string",
  "description": "The compiler to be used for C."
  },
  + {
  + "type": "null",
  + "description": "Setting a variable to null causes it to not be set, even if a value was inherited from another preset."
  + },
  {
  "type": "object",
  "properties": {
  "type": "string",
  "description": "The compiler to be used for C++."
  },
  + {
  + "type": "null",
  + "description": "Setting a variable to null causes it to not be set, even if a value was inherited from another preset."
  + },
  {
  "type": "object",
  "properties": {
  "type": "string",
  "description": "Install directory used by CMake."
  },
  + {
  + "type": "null",
  + "description": "Setting a variable to null causes it to not be set, even if a value was inherited from another preset."
  + },
  {
  "type": "object",
  "properties": {
  "type": "string",
  "description": "The toolchain file passed to CMake."
  },
  + {
  + "type": "null",
  + "description": "Setting a variable to null causes it to not be set, even if a value was inherited from another preset."
  + },
  {
  "type": "object",
  "properties": {
  ]
  },
  "CMAKE_BUILD_TYPE": {
  + "description": "Specifies the build type on single-configuration generators.",
  "anyOf": [
  {
  "type": "string",
  - "description": "Specifies the build type on single-configuration generators.",
  "enum": [
  "Debug",
  "Release",
  }
  },
  "additionalProperties": false
  + },
  + {
  + "type": "string"
  + },
  + {
  + "type": "null",
  + "description": "Setting a variable to null causes it to not be set, even if a value was inherited from another preset."
  }
  ]
  }
  