Promote multiple validation-gen tags to beta

This commit promotes the following validation-gen tags from alpha to beta:
- customUnique
- eachKey
- ifDisabled
- ifEnabled
- immutable
- unique
- update

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/each.go

@@ -309,7 +309,7 @@ func (ektv eachKeyTagValidator) Docs() TagDoc {
 	doc := TagDoc{
 		Tag:            ektv.TagName(),
 		Scopes:         ektv.ValidScopes().UnsortedList(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Description:    "Declares a validation for each value in a map or list.",
 		Payloads: []TagPayloadDoc{{
 			Description: "<validation-tag>",

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/immutable.go

@@ -59,7 +59,7 @@ func (immutableTagValidator) GetValidations(context Context, _ codetags.Tag) (Va
 func (itv immutableTagValidator) Docs() TagDoc {
 	return TagDoc{
 		Tag:            itv.TagName(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Scopes:         itv.ValidScopes().UnsortedList(),
 		Description:    "Indicates that a field may not be updated.",
 	}

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/list.go

@@ -323,7 +323,7 @@ func (utv uniqueTagValidator) GetValidations(context Context, tag codetags.Tag)
 func (utv uniqueTagValidator) Docs() TagDoc {
 	doc := TagDoc{
 		Tag:            utv.TagName(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Scopes:         utv.ValidScopes().UnsortedList(),
 		Description:    "Declares that a list field's elements are unique. This tag can be used with listType=atomic to add uniqueness constraints, or independently to specify uniqueness semantics.",
 		Payloads: []TagPayloadDoc{{
@@ -373,7 +373,7 @@ func (cutv customUniqueTagValidator) GetValidations(context Context, tag codetag
 func (cutv customUniqueTagValidator) Docs() TagDoc {
 	doc := TagDoc{
 		Tag:            cutv.TagName(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Scopes:         cutv.ValidScopes().UnsortedList(),
 		Description:    "Indicates that uniqueness validation for this list is implemented via custom, handwritten validation. This disables generation of uniqueness validation for this list.",
 		Payloads:       nil,

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/options.go

@@ -81,7 +81,7 @@ func (itv ifTagValidator) GetValidations(context Context, tag codetags.Tag) (Val
 func (itv ifTagValidator) Docs() TagDoc {
 	doc := TagDoc{
 		Tag:            itv.TagName(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Args: []TagArgDoc{{
 			Description: "<option>",
 			Type:        codetags.ArgTypeString,

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/update.go

@@ -134,7 +134,7 @@ func constraintName(c validate.UpdateConstraint) string {
 func (utc updateTagCollector) Docs() TagDoc {
 	return TagDoc{
 		Tag:            utc.TagName(),
-		StabilityLevel: TagStabilityLevelAlpha,
+		StabilityLevel: TagStabilityLevelBeta,
 		Scopes:         utc.ValidScopes().UnsortedList(),
 		PayloadsType:   codetags.ValueTypeString,
 		Description: "Provides constraints on the allowed update operations of a field. " +