feat(lifesciences): update the API

#### lifesciences:v2beta
The following keys were added:
- schemas.VirtualMachine.properties.dockerCacheImages.description
- schemas.VirtualMachine.properties.dockerCacheImages.items.type
- schemas.VirtualMachine.properties.dockerCacheImages.type

discovery/lifesciences-v2beta.json

@@ -312,7 +312,7 @@
       }
     }
   },
-  "revision": "20200507",
+  "revision": "20200625",
   "rootUrl": "https://lifesciences.googleapis.com/",
   "schemas": {
     "Accelerator": {
@@ -1039,6 +1039,13 @@
           },
           "type": "array"
         },
+        "dockerCacheImages": {
+          "description": "The Compute Engine Disk Images to use as a Docker cache. The disks will be\nmounted into the Docker folder in a way that the images present in the\ncache will not need to be pulled. The digests of the cached images must\nmatch those of the tags used or the latest version will still be pulled.\nOnly a single image is supported.",
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
         "enableStackdriverMonitoring": {
           "description": "Whether Stackdriver monitoring should be enabled on the VM.",
           "type": "boolean"

src/apis/lifesciences/v2beta.ts

@@ -660,6 +660,10 @@ export namespace lifesciences_v2beta {
      * The list of disks to create and attach to the VM.
      */
     disks?: Schema$Disk[];
+    /**
+     * The Compute Engine Disk Images to use as a Docker cache. The disks will be mounted into the Docker folder in a way that the images present in the cache will not need to be pulled. The digests of the cached images must match those of the tags used or the latest version will still be pulled. Only a single image is supported.
+     */
+    dockerCacheImages?: string[] | null;
     /**
      * Whether Stackdriver monitoring should be enabled on the VM.
      */