Update checkstyle

Author: will-molloy

checkstyle.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE module PUBLIC
-    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
-    "https://checkstyle.org/dtds/configuration_1_3.dtd">
+  "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+  "https://checkstyle.org/dtds/configuration_1_3.dtd">
 
 <!--
     Based on google_checks.xml
@@ -162,7 +162,7 @@
       <property name="option" value="nl"/>
     </module>
     <module name="PackageName">
-      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
+      <property name="format" value="^[a-z]+(\.[a-z_][a-z0-9]*)*$"/>
       <message key="name.invalidPattern"
                value="Package name ''{0}'' must match pattern ''{1}''."/>
     </module>
@@ -305,10 +305,10 @@
       <property name="scope" value="public"/>
       <property name="minLineCount" value="2"/>
       <property name="allowedAnnotations" value="Override, Test"/>
-      <property name="tokens" value="METHOD_DEF, ANNOTATION_FIELD_DEF"/>
+      <property name="tokens" value="METHOD_DEF, CTOR_DEF, ANNOTATION_FIELD_DEF"/>
     </module>
     <module name="MethodName">
-      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
+      <property name="format" value="^[a-z][a-zA-Z0-9_]*$"/>
       <message key="name.invalidPattern"
                value="Method name ''{0}'' must match pattern ''{1}''."/>
     </module>