Rename 'RetryType' to 'UnitRetryType'.

[fr33r]

Description

Renames work.RetryType to work.UnitRetryDelayType. Aliases work.UnitRetryDelayType as unit.RetryDelayType

Rationale

• Maintains consistency with existing type names.
• There is already an option called work.UnitRetryType, so work.UnitRetryDelayType is used to disambiguate.

Suggested Version

v4.0.0-beta

Example Usage

delayType := unit.RetryDelayTypeFixed
opts := []unit.Option{
  // ...
  unit.RetryType(delayType)
  // ...
}
u, err := unit.New(opts...)