Sourced from pyyaml's changelog.

5.3.1 (2020-03-18)

• yaml/pyyaml#386 -- Prevents arbitrary code execution during python/object/new constructor

5.3 (2020-01-06)

• yaml/pyyaml#290 -- Use is instead of equality for comparing with None
• yaml/pyyaml#270 -- fix typos and stylistic nit
• yaml/pyyaml#309 -- Fix up small typo
• yaml/pyyaml#161 -- Fix handling of slots
• yaml/pyyaml#358 -- Allow calling add_multi_constructor with None
• yaml/pyyaml#285 -- Add use of safe_load() function in README
• yaml/pyyaml#351 -- Fix reader for Unicode code points over 0xFFFF
• yaml/pyyaml#360 -- Enable certain unicode tests when maxunicode not > 0xffff
• yaml/pyyaml#359 -- Use full_load in yaml-highlight example
• yaml/pyyaml#244 -- Document that PyYAML is implemented with Cython
• yaml/pyyaml#329 -- Fix for Python 3.10
• yaml/pyyaml#310 -- increase size of index, line, and column fields
• yaml/pyyaml#260 -- remove some unused imports
• yaml/pyyaml#163 -- Create timezone-aware datetimes when parsed as such
• yaml/pyyaml#363 -- Add tests for timezone

5.2 (2019-12-02)

• Repair incompatibilities introduced with 5.1. The default Loader was changed, but several methods like add_constructor still used the old default yaml/pyyaml#279 -- A more flexible fix for custom tag constructors yaml/pyyaml#287 -- Change default loader for yaml.add_constructor yaml/pyyaml#305 -- Change default loader for add_implicit_resolver, add_path_resolver
• Make FullLoader safer by removing python/object/apply from the default FullLoader yaml/pyyaml#347 -- Move constructor for object/apply to UnsafeConstructor
• Fix bug introduced in 5.1 where quoting went wrong on systems with sys.maxunicode <= 0xffff yaml/pyyaml#276 -- Fix logic for quoting special characters
• Other PRs: yaml/pyyaml#280 -- Update CHANGES for 5.1

5.1.2 (2019-07-30)

• Re-release of 5.1 with regenerated Cython sources to build properly for Python 3.8b2+

5.1.1 (2019-06-05)

• Re-release of 5.1 with regenerated Cython sources to build properly for Python 3.8b1

• 538b5c9 Update announcement.msg
• 8a01c99 Move test files back into tests/data/
• 91bca4b Update version to 5.3.1
• 5080ba5 Prevents arbitrary code execution during python/object/new constructor (#386)
• 2f463cf Update announcement.msg
• 377092f Changes for 5.3
• 69b025a Changes for 5.3b1
• 4fcdcdb Add tests for timezone (#363)
• 96d65f3 Create timezone-aware datetimes when parsed as such (#163)
• 49b3548 tox.ini: passenv = PYYAML_TEST_GROUP
• Additional commits viewable in compare view

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