Bump com.google.errorprone:error_prone_core from 2.20.0 to 2.21.1 (#2463)

Suppress a couple of new Error Prone warnings.

gson/src/main/java/com/google/gson/internal/bind/TypeAdapters.java

@@ -570,7 +570,11 @@ public final class TypeAdapters {
         return null;
       }
       // regrettably, this should have included both the host name and the host address
-      return InetAddress.getByName(in.nextString());
+      // For compatibility, we use InetAddress.getByName rather than the possibly-better
+      // .getAllByName
+      @SuppressWarnings("AddressSelection")
+      InetAddress addr = InetAddress.getByName(in.nextString());
+      return addr;
     }
     @Override
     public void write(JsonWriter out, InetAddress value) throws IOException {

gson/src/test/java/com/google/gson/DefaultInetAddressTypeAdapterTest.java

@@ -37,6 +37,7 @@ public class DefaultInetAddressTypeAdapterTest {
   
   @Test
   public void testInetAddressSerializationAndDeserialization() throws Exception {
+    @SuppressWarnings("AddressSelection") // we really do want this method
     InetAddress address = InetAddress.getByName("8.8.8.8");
     String jsonAddress = gson.toJson(address);
     assertThat(jsonAddress).isEqualTo("\"8.8.8.8\"");

pom.xml

@@ -150,7 +150,7 @@
               <path>
                 <groupId>com.google.errorprone</groupId>
                 <artifactId>error_prone_core</artifactId>
-                <version>2.20.0</version>
+                <version>2.21.1</version>
               </path>
             </annotationProcessorPaths>
           </configuration>