Fix issue where PR without any description has its title edited

[Mariatta]

This came up in python/cpython#5291

The PR did not have any description, and the title was
edited to include the bpo number.
It caused a 500 error, because bedevere did not anticipate
this situation.

Updated the code so that it takes into consideration when the
body is empty.

[Mariatta]

Thanks @brettcannon for the quick review!
But tests failed in 3.7 😥 ironically about asyncio stuff which I have no idea about @1st1
https://travis-ci.org/python/bedevere/jobs/332943652#L568

[brettcannon]

Looks like the version of pytest-asyncio is too old to be compatible with the new async keyword change in 3.7.

@Mariatta Can you update the pytest-asyncio dependency in your PR and see if that fixes it? (Also feel free to update any other dependencies you want.)

[brettcannon]

I also just turned on pyup.io on this repo to help prevent this issue going forward.

[brettcannon]

Looks like pyup.io pushed #81 which should hopefully fix this.

[Mariatta]

Thanks! I'll rebase to get the latest changes.

[brettcannon]

#81 seems to do the trick, so probably just a merge off of master now will do the trick.

[codecov]

Codecov Report

Merging #79 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #79   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          14     14           
  Lines         974    980    +6     
  Branches       56     56           
=====================================
+ Hits          974    980    +6

Impacted Files	Coverage Δ
bedevere/bpo.py	100% <100%> (ø)	⬆️
tests/test_bpo.py	100% <100%> (ø)	⬆️

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