Upgrade maven from 3.5.2 to 3.6.1. Upgrade maven plugins:

- Bump jacoco-maven-plugin from 0.8.2 to 0.8.4
- Bump scala-maven-plugin from 3.2.2 to 4.0.2
- Bump maven-source-plugin from 3.0.1 to 3.1.0
- Bump maven-checkstyle-plugin from 3.0.0 to 3.1.0
- Bump maven-jar-plugin from 3.1.0 to 3.1.2
- Bump maven-surefire-plugin from 2.22.0 to 2.22.2.

Signed-off-by: Craig P. Motlin <[email protected]>

.travis.yml

@@ -3,7 +3,7 @@ dist: trusty
 sudo: false
 
 before_install:
-  - mvn -N io.takari:maven:wrapper -Dmaven=3.5.2
+  - mvn -N io.takari:maven:wrapper -Dmaven=3.6.1
   - echo "MAVEN_OPTS='-Dmaven.repo.local=$HOME/.m2/repository -Xmx1g -Dorg.slf4j.simpleLogger.showDateTime=true -Dorg.slf4j.simpleLogger.dateTimeFormat=HH:mm:ss:SSS'" > ~/.mavenrc
 
 install:

pom.xml

@@ -124,9 +124,9 @@
         <guava.version>25.1-jre</guava.version>
         <trove4j.version>3.0.3</trove4j.version>
         <checkstyle.version>8.11</checkstyle.version>
-        <checkstyle.plugin.version>3.0.0</checkstyle.plugin.version>
+        <checkstyle.plugin.version>3.1.0</checkstyle.plugin.version>
         <findbugs.plugin.version>3.0.5</findbugs.plugin.version>
-        <jacoco.plugin.version>0.8.2</jacoco.plugin.version>
+        <jacoco.plugin.version>0.8.4</jacoco.plugin.version>
 
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
@@ -259,7 +259,7 @@
 
                 <plugin>
                     <artifactId>maven-jar-plugin</artifactId>
-                    <version>3.1.0</version>
+                    <version>3.1.2</version>
                 </plugin>
 
                 <plugin>
@@ -289,7 +289,7 @@
 
                 <plugin>
                     <artifactId>maven-source-plugin</artifactId>
-                    <version>3.0.1</version>
+                    <version>3.1.0</version>
                     <executions>
                         <execution>
                             <phase>verify</phase>
@@ -347,7 +347,7 @@
                 <plugin>
                     <groupId>net.alchim31.maven</groupId>
                     <artifactId>scala-maven-plugin</artifactId>
-                    <version>3.2.2</version>
+                    <version>4.0.2</version>
                     <configuration>
                         <scalaVersion>${scala.version}</scalaVersion>
                     </configuration>
@@ -377,7 +377,7 @@
 
                 <plugin>
                     <artifactId>maven-surefire-plugin</artifactId>
-                    <version>2.22.0</version>
+                    <version>2.22.2</version>
                     <configuration>
                         <includes>
                             <include>**/*Test.java</include>