Update matplotlib font-cache (#4206)

* Update matplotlib font-cache

* Make CI happy, maybe

Author: martinRenou

recipes/recipes_emscripten/matplotlib/recipe.yaml

@@ -10,7 +10,7 @@ source:
   - patches/static-cast.patch
 
 build:
-  number: 0
+  number: 1
 
 outputs:
 - package:
@@ -51,6 +51,16 @@ outputs:
     - pyparsing
     - python-dateutil
     - pytz
+  tests:
+  - script: pytester
+    files:
+      recipe:
+      - test_import_matplotlib.py
+    requirements:
+      build:
+      - pytester
+      run:
+      - pytester-run
 
 - package:
     name: matplotlib