Update samples for sync_master_230

[ePaul]

PR checklist

• Read the contribution guidelines.
• Ran the shell/batch script under ./bin/ to update Petstore sample so that CIs can verify the change.
  → updated all the samples (except clojure and scalatra's build.sbt change – those were fixed in master, but not yet here).
• Filed the PR against the correct branch: sync_master_230 (which is intended to be later merged into 2.3.0)

Description of the PR

This updates all the samples after the merge of master and 2.3.0 so CI (and people) can check the results.

[ePaul]

Okay, at least Travis likes it.
Appveyor has problems finding io.swagger:swagger-parser:jar:1.0.26-SNAPSHOT in Sonatype,
Shippable has problems with JAVA_HOME.

I guess the latter will be fixed by merging in a newer master version.

[ePaul]

As discussed in #5056, I updated swagger-parser to 1.0.28. I also cherry-picked two commits from @fehguy from master (fixes for BashClientCodegen, which broke by the update). (I will rebase #5056 onto this one.)