As the title says, just a little fix to include gamemode switching for members of a plot to automatically switch into the default plot gamemode as specified in the config.yml when they enter it.

Also, we reworded the previous config.yml line 'force-plot-gamemode':
# Set forced change to plot gamemode when players enter their plot
to be a little clearer on what it does by changing it 'lock-plot-gamemode' instead:
#Lock gamemode to plot default when player enters their plot (disables '/plot gm' command)