pystring: add 1.1.4 + modernize more

[SpaceIm]

Specify library name and version: lib/1.0

This is also a good place to share with all of us why you are submitting this PR (specially if it is a new addition to ConanCenter): is it a dependency of other libraries you want to package? Are you the author of the library? Thanks!

---

• I've read the contributing guidelines.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the conan-center hook activated.

[conan-center-bot]

Conan v1 pipeline

All green in build 2 (03963872922df4f6c373539faaa40be60b98a1a0):

• pystring/1.1.3@:
  All packages built successfully! (All logs)

• pystring/1.1.4@:
  All packages built successfully! (All logs)

[github-actions]

Hooks produced the following warnings for commit 0396387

pystring/1.1.4

post_package(): WARN: [MISSING SYSTEM LIBS (KB-H043)] Library './lib/libpystring.so' links to system library 'm' but it is not in cpp_info.system_libs.

[uilianries]

LGTM