Replace deprecated FormatChecker.cls_checks

The method was deprecated in jsonschema 4.14.0[1] and now triggers
the following warning.

DeprecationWarning: FormatChecker.cls_checks is deprecated. Call
FormatChecker.checks on a specific FormatChecker instance instead.

[1] https://github.com/python-jsonschema/jsonschema/commit/cd8f0592b93947a9deb8b3e6502cc5a69cb6d722

Also resolve the following warning at the same time.

DeprecationWarning: Accessing jsonschema.draft4_format_checker is
deprecated and will be removed in a future release. Instead, use
the FORMAT_CHECKER attribute on the corresponding Validator.

Closes-Bug: #2089051
Related-Bug: #2008490
Change-Id: I0060e36d0be51cbafca5fef39c11178d2521f23a
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>
2 files changed