Fix CLI panic caused by single backslash values (#14523)

* upgrade go-secure-stdlib/kv-builder to v0.1.2

* add kv test to ensure single backslash values no longer panic

* add changelog entry

command/kv_test.go

@@ -141,6 +141,12 @@ func TestKVPutCommand(t *testing.T) {
 			[]string{"== Secret Path ==", "kv/data/write/foo"},
 			0,
 		},
+		{
+			"v2_single_value_backslash",
+			[]string{"kv/write/foo", "foo=\\"},
+			[]string{"== Secret Path ==", "kv/data/write/foo"},
+			0,
+		},
 	}
 
 	for _, tc := range cases {