replaced fixed mpl-data path in matplotlib __init__.py file, maybe fixes T234

AppImageBuilder.yml

@@ -49,9 +49,12 @@ AppDir:
       - python3-pyqtgraph
       - python3-tk
     exclude:
-      - usr/share/man
-      - usr/share/doc
-
+      - libavahi-client3
+      - libavahi-common-data
+      - libavahi-common3
+  after_bundle: |
+    echo "MONSTER SED FOLLOWING..."
+    sed -i s,\'/usr/share/matplotlib/mpl-data\',"f\"\{os.environ.get\('APPDIR'\,'/'\)\}/usr/share/matplotlib/mpl-data\"", ${TARGET_APPDIR}/usr/lib/python3/dist-packages/matplotlib/__init__.py
   runtime:
     version: "continuous"
     env: