Rename audit event Digest type for policy commits (#3901)

Author: emcfarlane

private/gen/proto/go/buf/alpha/audit/v1alpha1/event.pb.go

@@ -604,8 +604,8 @@ message PayloadPolicyCommitPushed {
   string policy_id = 3;
   // policy_name is the name of the policy within which the commit was created.
   string policy_name = 4;
-  // p1_digest is the p1 digest of the pushed policy commit.
-  string p1_digest = 5;
+  // o1_digest is the o1 digest of the pushed policy commit.
+  string o1_digest = 5;
 }
 
 message PayloadPluginCreated {