Release 0.33.3

[pirapira]

What this PR does

This PR marks the release 0.33.3

Why I'm making this PR

0.33.2 is broken #1298

What's tricky about this PR (if any)

This is probably the simplest possible release PR in this repo.

[skip ci]

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Any reviewer can check these:

• Squash unnecessary commits
• Comment commits

And before "merge" all checkboxes have to be checked. If you find redundant points, remove them.

[pirapira]

I've made sure that the change fixes the problem seen in raiden-network/raiden#5122 (comment).

[codecov]

Codecov Report

Merging #1302 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1302   +/-   ##
=======================================
  Coverage   81.76%   81.76%           
=======================================
  Files          21       21           
  Lines        1464     1464           
  Branches      193      193           
=======================================
  Hits         1197     1197           
  Misses        228      228           
  Partials       39       39

---

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[pirapira]

Perhaps this is a good moment to start with the easier versioning scheme.

[pirapira]

After the version scheme change, I'll make a release PR again.