Fix README links to Stackdriver Configuration (#2527)

Author: TheRoyalTnetennba

google-cloud-debugger/README.md

@@ -219,7 +219,7 @@ agent.
 You can customize the behavior of the Stackdriver Debugger agent. This includes
 setting the Google Cloud project and authentication, and customizing the
 behavior of the debugger itself, such as side effect protection and data
-size limits. See [agent configuration](../stackdriver/CONFIGURATION.md)
+size limits. See [agent configuration](../stackdriver/INSTRUMENTATION_CONFIGURATION.md)
 for a list of possible configuration options.
 
 ## Enabling Logging

google-cloud-logging/README.md

@@ -112,7 +112,7 @@ logger.
 ### Configuring the framework integration
 
 You can customize the behavior of the Stackdriver Logging framework integration
-for Ruby. See the [configuration guide](../stackdriver/CONFIGURATION.md) for a
+for Ruby. See the [configuration guide](../stackdriver/INSTRUMENTATION_CONFIGURATION.md) for a
 list of possible configuration options.
 
 ## Authentication

google-cloud-trace/README.md

@@ -94,7 +94,7 @@ end
 ### Configuring the library
 
 You can customize the behavior of the Stackdriver Trace library for Ruby. See
-the [configuration guide](../stackdriver/CONFIGURATION.md) for a list of
+the [configuration guide](../stackdriver/INSTRUMENTATION_CONFIGURATION.md) for a list of
 possible configuration options.
 
 ## Running on Google Cloud Platform