Bump checkstyle-plugin to 3.1.1. (#208)

Author: kurtisvg

connector-j-8/src/main/java/com/google/cloud/sql/mysql/SocketFactory.java

@@ -52,7 +52,8 @@ public <T extends Closeable> T connect(
   // Cloud SQL sockets always use TLS and the socket returned by connect above is already TLS-ready.
   // It is fine to implement these as no-ops.
   @Override
-  public void beforeHandshake() {}
+  public void beforeHandshake() {
+  }
 
   @Override
   public <T extends Closeable> T performTlsHandshake(
@@ -63,5 +64,6 @@ public <T extends Closeable> T performTlsHandshake(
   }
 
   @Override
-  public void afterHandshake() {}
+  public void afterHandshake() {
+  }
 }

pom.xml

@@ -139,7 +139,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-checkstyle-plugin</artifactId>
-        <version>3.1.0</version>
+        <version>3.1.1</version>
         <configuration>
           <configLocation>google_checks.xml</configLocation>
           <logViolationsToConsole>true</logViolationsToConsole>