Upgrade Fog version to fix progress bar issue

The upgrade of our supplier to 5.5 exposed an issue with the task progress bar in that it wasn't returned quickly enough so the code fell over. A fix was made in Fog https://github.com/fog/fog/pull/2837 and this commit bumps the required Fog version to take advantage of the fix.
Bump version of vCloud Core for progress bar fix
Wrong version number in CHANGELOG
Merge pull request #19 from alphagov/fix-progress-bar

[#69700312] Fix progress bar