title: Rotate latitude (y) tick labels - cartopy
body: <p>Is there a way to rotate the latitude tick labels in a cartopy map? I know it is a very easy and usual option in GIS programs such as QGIS, but I couldn't find anything on the subject when using cartopy.</p>
  
  <p>Below there's a simple example (I plot my own shapefiles, that I don't express here):</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import cartopy.crs as ccrs
  from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter
  
  mapp = plt.subplot(111, projection=ccrs.PlateCarree())
  mapp.set_extent([-44.2, -45.6, -23.36, -24.35])
  
  mapp.set_yticks([-23.5,-24], crs=ccrs.PlateCarree())
  mapp.set_xticks([-44.5,-45.5], crs=ccrs.PlateCarree())
  
  lon_formatter = LongitudeFormatter(number_format='.1f')
  lat_formatter = LatitudeFormatter(number_format='.1f')
  mapp.xaxis.set_major_formatter(lon_formatter)
  mapp.yaxis.set_major_formatter(lat_formatter)
  plt.show()
  </code></pre>
  
  <p>It's not the best MCVE, but anyway, it shows the latitude tick labels horizontally -- that's a standard. My question is: is there a way to rotate the latitude tick labels (or the y tick labels) in 90° so they get vertical?</p>