Section 4.2 of RFC 7636 mentions the ABNF form to which the code challenge should adhere. authlib currently accepts any string in code_challenge without validating if it matches the format specified in the RFC. Fix the same and also update relevant tests.
What kind of change does this PR introduce? (check at least one)
[X] Bugfix
[ ] Feature
[ ] Code style update
[ ] Refactor
[ ] Other, please describe:
[X] You consent that the copyright of your pull request source code belongs to Authlib's author.
Section 4.2 of RFC 7636 mentions the ABNF form to which the code challenge should adhere. authlib currently accepts any string in code_challenge without validating if it matches the format specified in the RFC. Fix the same and also update relevant tests.
What kind of change does this PR introduce? (check at least one)