Use Bool type for boolean columns in ClickHouse

In earlier versions of ClickHouse, the `UInt8` type had to be used,
but now this is causing trouble with NumPy bool arrays.

Author: michaelosthege

mcbackend/backends/clickhouse.py

@@ -29,7 +29,7 @@
     "int64": "Int64",
     "float32": "Float32",
     "float64": "Float64",
-    "bool": "UInt8",
+    "bool": "Bool",
     "str": "String",
 }
 

mcbackend/test_backend_clickhouse.py

@@ -202,7 +202,7 @@ def test_create_chain_table(self):
             ("scalar", "UInt16"),
             ("1D", "Array(Float32)"),
             ("3D", "Array(Array(Array(Float64)))"),
-            ("__stat_accepted", "UInt8"),
+            ("__stat_accepted", "Bool"),
         ]
         pass