housekeeping: Updated Cake to v0.38.1

[RLittlesII]

What kind of change does this PR introduce?

Updates Cake to v0.38.1

What is the current behavior?

The most updated version of ReactiveUI.Cake.Recipe is broken

What is the new behavior?

The ReactiveUI.Cake.Recipe works

What might this PR break?

Nothing

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:

[codecov]

Codecov Report

Merging #91 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #91   +/-   ##
=======================================
  Coverage   63.87%   63.87%           
=======================================
  Files           6        6           
  Lines         299      299           
  Branches       52       52           
=======================================
  Hits          191      191           
  Misses         96       96           
  Partials       12       12           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e755232...f15fa42. Read the comment docs.