Fixed the copy of the missing data file (#58)

Author: cereal2nd

MANIFEST.IN

@@ -1,3 +1,4 @@
 recursive-include velbus *.py
+include velbus/data.json
 include README.txt
 include setup.py

setup.py

@@ -2,11 +2,12 @@
 
 setup(
     name="python-velbus",
-    version="2.0.41",
+    version="2.0.42",
     url="https://github.com/thomasdelaet/python-velbus",
     license="MIT",
     author="Thomas Delaet",
     install_requires=["pyserial==3.3"],
     author_email="thomas@delaet.org",
     packages=["velbus", "velbus.connections", "velbus.messages", "velbus.modules"],
+    include_package_data=True,
 )