package/ci: go back to Pelican 4.2 until I find a fix.

OH GOD, one can't just leave a project alone for 6 months because every
damn thing just breaks, changes or gets removed. Kids these days, FFS.

Imagine if the standard of electrical outlets changed rapidly every two
weeks, you'd just have to constantly buy new fucking adapters and you
would HATE it. So why is it COMPLETELY FINE with software?!

package/ci/travis.yml

@@ -54,7 +54,9 @@ matrix:
       - JOBID=js
 
 install:
-  - if [ "$WITH_THEME" == "ON" ]; then pip install jinja2 pelican Pyphen Pillow coverage codecov matplotlib qrcode; fi
+  # Everything broken with Pelican 4.5, stay on older version until that's
+  # resolved: https://github.com/mosra/m.css/issues/178
+  - if [ "$WITH_THEME" == "ON" ]; then pip install jinja2 pelican==4.2.0 Pyphen Pillow coverage codecov matplotlib qrcode; fi
   - if [ "$WITH_NODE" == "ON" ]; then npm install istanbul codecov; fi
 
   # Needed for doxygen binaries