Downgrade pillow so commands like 'caption' can run

[pankofufu]

This fixes the error object 'ImageDraw' has no attribute 'textsize' that occurs when running commands like caption, toptext and bottomtext. See: https://groups.google.com/g/weewx-user/c/4qz0bwgna7g?pli=1

When using a modified version of the bot code that returns error messages, I get the error:

[GanerCodes]

W