separate constant with underscore.

Author: rmehta19

oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java

@@ -130,7 +130,7 @@ public enum BindingEnforcement {
     // Binding enforcement will always happen, irrespective of the IAM policy.
     ON("on"),
     // Binding enforcement will depend on IAM policy.
-    IAMPOLICY("iam-policy");
+    IAM_POLICY("iam-policy");
 
     private final String label;
 

oauth2_http/javatests/com/google/auth/oauth2/ComputeEngineCredentialsTest.java

@@ -229,7 +229,7 @@ public void buildTokenUrlSoftMtlsBound_mtls_transport() {
   public void buildTokenUrlSoftMtlsBound_iam_enforcement() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.IAMPOLICY)
+            .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.IAM_POLICY)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();
 
@@ -241,7 +241,7 @@ public void buildTokenUrlSoftMtlsBound_mtls_transport_iam_enforcement() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
             .setTransport(ComputeEngineCredentials.AuthTransport.MTLS)
-            .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.IAMPOLICY)
+            .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.IAM_POLICY)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();