Add dependency on pytango

Just like numpy, pytango is a (core) dependency of this package, but it
had never been specified in the install_requires list. This commit fixes
that.

This problem was found while working on YAN-685.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

README.md

@@ -26,7 +26,7 @@ The ska-tango-base repository includes a set of eight classes as mentioned in SK
 ## Version History
 
 #### Not released yet
-- Make dependency on `numpy` python package explicit.
+- Make dependency on `pytango` and `numpy` python packages explicit.
 
 #### 0.10.0
 - Add `DebugDevice` command to `SKABaseDevice`.  This allows remote debugging to be

setup.py

@@ -35,7 +35,7 @@ setuptools.setup(
     ],
     platforms=["OS Independent"],
     setup_requires=[] + pytest_runner,
-    install_requires=["debugpy", "numpy", "transitions", "ska_ser_logging"],
+    install_requires=["debugpy", "numpy", "pytango", "transitions", "ska_ser_logging"],
     tests_require=["pytest", "coverage", "pytest-json-report", "pytest-forked"],
     entry_points={
         "console_scripts": [