[flatpak] fix -> crashing when an update size cannot be read

CHANGELOG.md

@@ -41,6 +41,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Flatpak
     - downgrading crashing with version 1.8.X
     - history: the top commit is returned as "(null)" in version 1.8.X
+    - crashing when an update size cannot be read [#130](https://github.com/vinifmor/bauh/issues/130)
     - installation fails when there are multiple references for a given package (e.g: openh264)
      <p align="center">
         <img src="https://raw.githubusercontent.com/vinifmor/bauh/staging/pictures/releases/0.9.7/flatpak_refs.png">

bauh/gems/flatpak/flatpak.py

@@ -415,5 +415,10 @@ def map_update_download_size(app_ids: Iterable[str], installation: str, version:
 
                         if related_id:
                             size = p2.findall(line_split[6])[0].split('?')
-                            res[related_id[0].strip()] = size_to_byte(float(size[0]), size[1])
+
+                            if size and len(size) > 1:
+                                try:
+                                    res[related_id[0].strip()] = size_to_byte(float(size[0]), size[1])
+                                except:
+                                    traceback.print_exc()
         return res