Bump protoc version

MOE_MIGRATED_REVID=136856567
diff --git a/pom.xml b/pom.xml
index 5d7b19f..9e26ce3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -33,7 +33,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>3.0.2</version>
+      <version>3.1.0</version>
     </dependency>
     <dependency>
       <groupId>org.ow2.asm</groupId>
@@ -88,7 +88,7 @@
       <extension>
         <groupId>kr.motd.maven</groupId>
         <artifactId>os-maven-plugin</artifactId>
-        <version>1.4.1.Final</version>
+        <version>1.4.0.Final</version>
       </extension>
     </extensions>
     <plugins>
@@ -108,7 +108,7 @@
         <version>0.5.0</version>
         <configuration>
           <protoSourceRoot>proto</protoSourceRoot>
-          <protocArtifact>com.google.protobuf:protoc:3.0.2:exe:${os.detected.classifier}</protocArtifact>
+          <protocArtifact>com.google.protobuf:protoc:3.1.0:exe:${os.detected.classifier}</protocArtifact>
           <pluginId>grpc-java</pluginId>
           <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.0.1:exe:${os.detected.classifier}</pluginArtifact>
         </configuration>