Make dimension limits Option<Integer> instead of using the magic value of 0 for "no limit", and add more tests for the ServerConfig.

pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
@@ -57,7 +58,7 @@
     <properties>
         <maze-generator.version>0.2.1</maze-generator.version>
         <maven-site-plugin.version>4.0.0-M8</maven-site-plugin.version>
-        <undertow.version>2.3.13.Final</undertow.version>
+        <undertow.version>2.3.18.Final</undertow.version>
     </properties>
 
     <dependencies>
@@ -95,6 +96,11 @@
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -104,7 +110,8 @@
                 <artifactId>maven-shade-plugin</artifactId>
                 <configuration>
                     <transformers>
-                        <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                        <transformer
+                                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                             <mainClass>ch.fritteli.maze.server.Main</mainClass>
                         </transformer>
                     </transformers>