Resolve merge errors

Author: cindy-peng

proto-google-cloud-datastore-v1/src/main/java/com/google/datastore/v1/Mutation.java

@@ -1264,6 +1264,7 @@ public com.google.datastore.v1.Mutation build() {
     @java.lang.Override
     public com.google.datastore.v1.Mutation buildPartial() {
       com.google.datastore.v1.Mutation result = new com.google.datastore.v1.Mutation(this);
+      buildPartialRepeatedFields(result);
       if (bitField0_ != 0) {
         buildPartial0(result);
       }

proto-google-cloud-datastore-v1/src/main/proto/google/datastore/v1/datastore.proto

@@ -501,6 +501,18 @@ message ReserveIdsResponse {}
 
 // A mutation to apply to an entity.
 message Mutation {
+  // The possible ways to resolve a conflict detected in a mutation.
+  enum ConflictResolutionStrategy {
+    // Unspecified. Defaults to `SERVER_VALUE`.
+    STRATEGY_UNSPECIFIED = 0;
+
+    // The server entity is kept.
+    SERVER_VALUE = 1;
+
+    // The whole commit request fails.
+    FAIL = 3;
+  }
+
   // The mutation operation.
   //
   // For `insert`, `update`, and `upsert`: