title: I can't upgrade cartopy to 0.18.0 using conda
body: <p>I'm trying to upgrade cartopy to version 0.18.0</p>
  <p>I tried <code>conda update cartopy</code> and it does nothing.</p>
  <p>I removed cartopy and tried to reinstall cartopy using <code>conda install -c conda-forge cartopy</code> and it tells me that is going to install version 0.17.0 and not 0.18.0.</p>
  <p>I finally tried to install it using <code>pip install cartopy</code>. PIP tries to install the version 0.18.0 but I get a different error here that I'm not able to solve:
  lib/cartopy/trace.cpp(665): fatal error C1083: No se puede abrir el archivo incluir: 'geos_c.h': No such file or directory</p>
  <p>I cannot understand why if 0.18.0 is the primary version of <a href="https://anaconda.org/conda-forge/cartopy" rel="nofollow noreferrer">cartopy in conda</a>, it tries to install a previous version. In Anaconda navigator there is also the old version (0.17.0). I'm using Anaconda for Windows 10.</p>