Bump to release version 2.28

PiperOrigin-RevId: 380650781
Change-Id: I8ec2cd013e21701b95af942d8c7ce47b75db4a37

Author: mctavish

src/agent/internals/src/main/java/com/google/devtools/cdbg/debuglets/java/GcpDebugletVersion.java

@@ -24,7 +24,7 @@ public final class GcpDebugletVersion {
   public static final int MAJOR_VERSION = 2;
 
   /** Minor version of the agent. */
-  public static final int MINOR_VERSION = 27;
+  public static final int MINOR_VERSION = 28;
 
   /** Debugger agent version string in the format of MAJOR.MINOR. */
   public static final String VERSION = String.format("%d.%d", MAJOR_VERSION, MINOR_VERSION);