[Bitbucket] Fixed broken update_file and upload_file API calls (fixes issue #1080)

[jnbolito]

This fixes issue #1080 by removing the Content-Type: application/json header set when updating/uploading files. The issue occurs because Content-Type: application/json is a part of the default headers sent out, explicitly. This in turn prevents requests from adding the multipart/form-data Content-Type required by the Bitbucket API (as per the reference).

[jnbolito]

Hi @gonchik, it seems the tests are failing due to reasons unrelated to my changes 😅 ...

flake8
atlassian/rest_client.py:10:5: F401 'oauthlib.oauth1.SIGNATURE_RSA_SHA512' imported but unused
atlassian/bamboo.py:1200:5: F811 redefinition of unused 'upload_plugin' from line 1103

mypy
atlassian/bamboo.py:1200: error: Name 'upload_plugin' already defined on line 1103

Shall I fix them?

[gonchik]

Hi!
I have adjusted, let me rerun it

[codecov-commenter]

Codecov Report

Base: 36.03% // Head: 36.03% // No change to project coverage 👍

Coverage data is based on head (b804ee2) compared to base (211f26b).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1092   +/-   ##
=======================================
  Coverage   36.03%   36.03%           
=======================================
  Files          38       38           
  Lines        7057     7057           
  Branches     1009     1009           
=======================================
  Hits         2543     2543           
  Misses       4407     4407           
  Partials      107      107           

Impacted Files	Coverage Δ
atlassian/bitbucket/__init__.py	29.96% <0.00%> (ø)
atlassian/service_desk.py	38.98% <ø> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[gonchik]

Thank you!