chore(main): release 0.278.0 (#8115)

Author: release-please[bot]

VERSION

@@ -1 +1 @@
-1.95.0
+1.96.0

src/SpannerClient.php

@@ -117,7 +117,7 @@ class SpannerClient
     use LROTrait;
     use ValidateTrait;
 
-    const VERSION = '1.95.0';
+    const VERSION = '1.96.0';
 
     const FULL_CONTROL_SCOPE = 'https://www.googleapis.com/auth/spanner.data';
     const ADMIN_SCOPE = 'https://www.googleapis.com/auth/spanner.admin';