chore: add clirr ignored diff

Author: olavloite

google-cloud-spanner/clirr-ignored-differences.xml

@@ -676,4 +676,11 @@
     <method>boolean isEnableExtendedTracing()</method>
   </difference>
 
+  <!-- Added API tracing option -->
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/SpannerOptions$SpannerEnvironment</className>
+    <method>boolean isEnableApiTracing()</method>
+  </difference>
+
 </differences>