Package pandas.tools.plotting was moved to pandas.plotting in this commit, as part of #16005 and #12548 in Pandas 0.20.0.
More recently, in this commit in Pandas #23376 released in Pandas 0.24.0, the deprecated pandas.tools package, which was previously allowing pandas.tools.plotting to keep working, was removed.
Ergo, once you allow Pandas to upgrade to 0.24.0 or later, you will need to replace imports from pandas.tools.plotting to be instead from pandas.plotting.