Update version for 5.1.0

Fix up bake value defaults for fixtures with enums (#982)

* Fix up bake value defaults for fixtures with enums

* Fix CS

* Prevent runtime error.

Merge pull request #976 from cakephp/3.next

next minor release 3.1.0

Merge pull request #974 from cakephp/3.x-stan-update

3.x: stan update

Merge pull request #966 from cakephp/3.x-fix-false-positive-file-fields

3.x - Fix fields being incorrectly detected as file fields.

Merge pull request #959 from cakephp/enum-entity-annotation

Fix annotation for entity field mapped to enum type.

Merge pull request #948 from markusramsak/patch-1

Update DocBlockHelper.php allow different date and time classes

Merge pull request #943 from CakeDC/feature/named-arguments

Use named arguments

Update to stable releases.

Merge branch '2.next' into 3.x