Add [PythonVersionFromToml] shield (#9516)

* Add PythonVersionFromToml

Added new shield per issue #9410
The shield display required python versions for packages based on pyproject.toml

* Add tests for PythonVersionFromToml

* Improve docs for tests regex

* Improve title and description

Rename and updated description to bring into focus that only PEP 621 complaint pyproject.toml files are supported.

Solves review https://github.com/badges/shields/pull/9516#discussion_r1310648023

* replace complex regex with @renovate/pep440

solves review https://github.com/badges/shields/pull/9516#discussion_r1310648881

services/python/python-version-from-toml.tester.js

@@ -0,0 +1,27 @@
+import Joi from 'joi'
+import pep440 from '@renovate/pep440'
+import { createServiceTester } from '../tester.js'
+export const t = await createServiceTester()
+
+const validatePep440 = (value, helpers) => {
+  if (!pep440.validRange(value)) {
+    return helpers.error('any.invalid')
+  }
+  return value
+}
+
+const isCommaSeparatedPythonVersions = Joi.string().custom(validatePep440)
+
+t.create('python versions (valid)')
+  .get(
+    '/python/required-version-toml.json?tomlFilePath=https://raw.githubusercontent.com/numpy/numpy/main/pyproject.toml',
+  )
+  .expectBadge({ label: 'python', message: isCommaSeparatedPythonVersions })
+
+t.create(
+  'python versions - valid toml with missing python-requires field (invalid)',
+)
+  .get(
+    '/python/required-version-toml.json?tomlFilePath=https://raw.githubusercontent.com/django/django/main/pyproject.toml',
+  )
+  .expectBadge({ label: 'python', message: 'invalid response data' })