feat(spanner): update the API

#### spanner:v1

The following keys were added:
- schemas.KeyRangeInfo.properties.timeOffset.description
- schemas.KeyRangeInfo.properties.timeOffset.format
- schemas.KeyRangeInfo.properties.timeOffset.type

discovery/spanner-v1.json

@@ -2037,7 +2037,7 @@
       }
     }
   },
-  "revision": "20210611",
+  "revision": "20210624",
   "rootUrl": "https://spanner.googleapis.com/",
   "schemas": {
     "Backup": {
@@ -2971,6 +2971,11 @@
           "format": "int32",
           "type": "integer"
         },
+        "timeOffset": {
+          "description": "The time offset. This is the time since the start of the time interval.",
+          "format": "google-duration",
+          "type": "string"
+        },
         "unit": {
           "$ref": "LocalizedString",
           "description": "The unit of the metric. This is an unstructured field and will be mapped as is to the user."

src/apis/spanner/v1.ts

@@ -795,6 +795,10 @@ export namespace spanner_v1 {
      * The index of the start key in indexed_keys.
      */
     startKeyIndex?: number | null;
+    /**
+     * The time offset. This is the time since the start of the time interval.
+     */
+    timeOffset?: string | null;
     /**
      * The unit of the metric. This is an unstructured field and will be mapped as is to the user.
      */