QGIS - Solve Launch alert on "python modules numpy and matplotlib both not installed"

When you start QGIS and got a screen start error that reads:-

The contour plugin is disabled as it requires python modules numpy and matplotlib which are not both installed.

This is custom error caused by a deprecated matplolib import command "from matplotlib.mlab import griddata". You can click on 'Ok' button to continue loading the QGIS software.

However, clicking on that button is somewhat annoying and you will definitely like to fix the error permanently.

The error comes from the 'contour' plugin that was installed in the plugins directory at: 
C:\Users\YourPcName\AppData\Roaming\QGIS\QGIS3\profiles\default\python\plugins\contour

Open the python file "ContourDialog.py" in your text editor. You would find and comment out the import statement "from matplotlib.mlab import griddata" and save the file.

This should fix the warning error massage from launching the software when you restart it.

The warning message box that pops up above is actually located in this same file somewhere below.

That is it!