feat(ci): set git describe as build number

Jenkinsfile

@@ -35,7 +35,7 @@ pipeline {
 
         stage('compile') {
             steps {
-                sh 'mvn clean package'
+                sh "BUILD_NUMBER=${version} mvn clean package"
             }
         }
 

pom.xml

@@ -6,16 +6,29 @@
 
     <groupId>de.hftstuttgart</groupId>
     <artifactId>modocot-openjdk11-junit5-runner</artifactId>
-    <version>1.0.0</version>
+    <version>${buildNumber}</version>
     <packaging>jar</packaging>
 
     <properties>
+        <buildNumber>devel</buildNumber>
         <java.version>8</java.version>
         <maven.compiler.source>8</maven.compiler.source>
         <maven.compiler.target>8</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
+    <profiles>
+        <profile>
+            <id>ci</id>
+            <activation>
+                <property><name>env.BUILD_NUMBER</name></property>
+            </activation>
+            <properties>
+                <buildNumber>${env.BUILD_NUMBER}</buildNumber>
+            </properties>
+        </profile>
+    </profiles>
+
     <dependencies>
         <dependency>
             <groupId>org.junit.jupiter</groupId>