adding missing dependency, otherwise changing khash.h does not trigger rebuild

Author: realead

setup.py

@@ -526,7 +526,9 @@ def srcpath(name=None, suffix=".pyx", subdir="src"):
     "_libs.hashtable": {
         "pyxfile": "_libs/hashtable",
         "include": klib_include,
-        "depends": (["pandas/_libs/src/klib/khash_python.h"] + _pxi_dep["hashtable"]),
+        "depends": ([
+            "pandas/_libs/src/klib/khash_python.h",
+            "pandas/_libs/src/klib/khash.h"] + _pxi_dep["hashtable"]),
     },
     "_libs.index": {
         "pyxfile": "_libs/index",