Flatpak: Update dependencies

and convert files to yaml to improve readability

flatpak/modules/python3-pillow.yaml

@@ -0,0 +1,11 @@
+name: python3-pillow
+ensure-writable:
+  - easy-install.pth
+buildsystem: simple
+build-commands:
+  - install -d ${FLATPAK_DEST}/lib/python3.7/site-packages/
+  - python3 setup.py install --prefix=${FLATPAK_DEST}
+sources:
+  - type: archive
+    url: https://files.pythonhosted.org/packages/1b/e1/1118d60e9946e4e77872b69c58bc2f28448ec02c99a2ce456cd1a272c5fd/Pillow-5.3.0.tar.gz
+    sha256: 2ea3517cd5779843de8a759c2349a3cd8d3893e03ab47053b66d5ec6f8bc4f93