Remove version number from opentelemetry exporter-trace dependency

Author: manu2

google-cloud-spanner/pom.xml

@@ -458,7 +458,6 @@
     <dependency>
       <groupId>com.google.cloud.opentelemetry</groupId>
       <artifactId>exporter-trace</artifactId>
-      <version>0.33.0</version>
       <scope>test</scope>
     </dependency>
     <dependency>