update kube and vendor dependencies

With kubernetes 1.18 release of client-go, signatures on methods in
generated clientsets, dynamic, metadata, and scale clients have been
modified to accept context.Context as a first argument.
Signatures of Create, Update, and Patch methods have been updated
to accept CreateOptions, UpdateOptions and PatchOptions respectively.
Signatures of Delete and DeleteCollection methods now accept
DeleteOptions by value instead of by reference.
These changes are now accommodated with this PR and client-go
and dependencies are updated to v1.18.0

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

vendor/k8s.io/client-go/tools/cache/store.go

@@ -23,27 +23,50 @@ import (
 	"k8s.io/apimachinery/pkg/api/meta"
 )
 
-// Store is a generic object storage interface. Reflector knows how to watch a server
-// and update a store. A generic store is provided, which allows Reflector to be used
-// as a local caching system, and an LRU store, which allows Reflector to work like a
-// queue of items yet to be processed.
+// Store is a generic object storage and processing interface.  A
+// Store holds a map from string keys to accumulators, and has
+// operations to add, update, and delete a given object to/from the
+// accumulator currently associated with a given key.  A Store also
+// knows how to extract the key from a given object, so many operations
+// are given only the object.
 //
-// Store makes no assumptions about stored object identity; it is the responsibility
-// of a Store implementation to provide a mechanism to correctly key objects and to
-// define the contract for obtaining objects by some arbitrary key type.
+// In the simplest Store implementations each accumulator is simply
+// the last given object, or empty after Delete, and thus the Store's
+// behavior is simple storage.
+//
+// Reflector knows how to watch a server and update a Store.  This
+// package provides a variety of implementations of Store.
 type Store interface {
+
+	// Add adds the given object to the accumulator associated with the given object's key
 	Add(obj interface{}) error
+
+	// Update updates the given object in the accumulator associated with the given object's key
 	Update(obj interface{}) error
+
+	// Delete deletes the given object from the accumulator associated with the given object's key
 	Delete(obj interface{}) error
+
+	// List returns a list of all the currently non-empty accumulators
 	List() []interface{}
+
+	// ListKeys returns a list of all the keys currently associated with non-empty accumulators
 	ListKeys() []string
+
+	// Get returns the accumulator associated with the given object's key
 	Get(obj interface{}) (item interface{}, exists bool, err error)
+
+	// GetByKey returns the accumulator associated with the given key
 	GetByKey(key string) (item interface{}, exists bool, err error)
 
 	// Replace will delete the contents of the store, using instead the
 	// given list. Store takes ownership of the list, you should not reference
 	// it after calling this function.
 	Replace([]interface{}, string) error
+
+	// Resync is meaningless in the terms appearing here but has
+	// meaning in some implementations that have non-trivial
+	// additional behavior (e.g., DeltaFIFO).
 	Resync() error
 }
 
@@ -106,9 +129,8 @@ func SplitMetaNamespaceKey(key string) (namespace, name string, err error) {
 	return "", "", fmt.Errorf("unexpected key format: %q", key)
 }
 
-// cache responsibilities are limited to:
-//	1. Computing keys for objects via keyFunc
-//  2. Invoking methods of a ThreadSafeStorage interface
+// `*cache` implements Indexer in terms of a ThreadSafeStore and an
+// associated KeyFunc.
 type cache struct {
 	// cacheStorage bears the burden of thread safety for the cache
 	cacheStorage ThreadSafeStore
@@ -222,9 +244,9 @@ func (c *cache) Replace(list []interface{}, resourceVersion string) error {
 	return nil
 }
 
-// Resync touches all items in the store to force processing
+// Resync is meaningless for one of these
 func (c *cache) Resync() error {
-	return c.cacheStorage.Resync()
+	return nil
 }
 
 // NewStore returns a Store implemented simply with a map and a lock.