Pynguin v0.12.0

• Generate more reasonable variable names in tests.
  Before this release, Pynguin only generated variables named var0, var1, etc.
  A simple heuristics now attempts to generate more reasonable names depending on the
  type of the variable, such as int_0, bool_1, or str_2.
  We also adjusted the documentation to match this change.
• We updated all provided PyCharm run configurations the use the more sophisticated
  queue example instead of the simple example module to see an improved output.
• Prevent a potential regression when updating the dependencies to version 0.0.17 of the
  simple-parsing library for CLI argument
  parsing, which changed its API.