[Python][R] Escape single quotes in strings

[fsonntag]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: master, 3.4.x, 4.0.x. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.
  @taxpon (2017/07) @frol (2017/07) @mbohlool (2017/07) @cbornet (2017/09) @kenjones-cisco (2017/11) @tomplus (2018/10) @Jyhess (2019/01)

Description of the PR

Escapes single quotes, so that the generated code does not break.

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[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/OpenAPITools/openapi-generator/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

[wing328]

The CI tests failed with the following error message:

[ERROR] Tests run: 657, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 14.887 s <<< FAILURE! - in TestSuite
[ERROR] testSingleQuotes1(org.openapitools.codegen.python.PythonClientCodegenTest)  Time elapsed: 0 s  <<< FAILURE!
java.lang.AssertionError: expected ['Text containing 'single' quote'] but found [Text containing 'single' quote]
	at org.openapitools.codegen.python.PythonClientCodegenTest.testSingleQuotes1(PythonClientCodegenTest.java:102)
[ERROR] Failures: 
[ERROR]   PythonClientCodegenTest.testSingleQuotes1:102 expected ['Text containing 'single' quote'] but found [Text containing 'single' quote]
[ERROR] Tests run: 657, Failures: 1, Errors: 0, Skipped: 0
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.22.1:test (default-test) on project openapi-generator: There are test failures.
[ERROR] 
[ERROR] Please refer to C:\projects\openapi-generator\modules\openapi-generator\target\surefire-reports for the individual test results.
[ERROR] Please refer to dump files (if any exist) [date].dump, [date]-jvmRun[N].dump and [date].dumpstream.
[ERROR] -> [Help 1]
[ERROR] 

Please have a look when you've time.

[fsonntag]

@wing328 Thanks for noticing both! Changed the authorship information, and fixed the test!