Bump golang/mock version to v1.3.1

vendor/github.com/golang/mock/gomock/matchers.go

@@ -98,9 +98,30 @@ func (m assignableToTypeOfMatcher) String() string {
 }
 
 // Constructors
-func Any() Matcher             { return anyMatcher{} }
+// Any returns a matcher that always matches.
+func Any() Matcher { return anyMatcher{} }
+
+// Eq returns a matcher that matches on equality.
+//
+// Example usage:
+//   Eq(5).Matches(5) // returns true
+//   Eq(5).Matches(4) // returns false
 func Eq(x interface{}) Matcher { return eqMatcher{x} }
-func Nil() Matcher             { return nilMatcher{} }
+
+// Nil returns a matcher that matches if the received value is nil.
+//
+// Example usage:
+//   var x *bytes.Buffer
+//   Nil().Matches(x) // returns true
+//   x = &bytes.Buffer{}
+//   Nil().Matches(x) // returns false
+func Nil() Matcher { return nilMatcher{} }
+
+// Not reverses the results of its given child matcher.
+//
+// Example usage:
+//   Not(Eq(5)).Matches(4) // returns true
+//   Not(Eq(5)).Matches(5) // returns false
 func Not(x interface{}) Matcher {
 	if m, ok := x.(Matcher); ok {
 		return notMatcher{m}
@@ -112,11 +133,9 @@ func Not(x interface{}) Matcher {
 // function is assignable to the type of the parameter to this function.
 //
 // Example usage:
-//
-// 		dbMock.EXPECT().
-// 			Insert(gomock.AssignableToTypeOf(&EmployeeRecord{})).
-// 			Return(errors.New("DB error"))
-//
+//   var s fmt.Stringer = &bytes.Buffer{}
+//   AssignableToTypeOf(s).Matches(time.Second) // returns true
+//   AssignableToTypeOf(s).Matches(99) // returns false
 func AssignableToTypeOf(x interface{}) Matcher {
 	return assignableToTypeOfMatcher{reflect.TypeOf(x)}
 }