Update dependencies

README.md

@@ -49,9 +49,6 @@ You will need at least Maven 3.5.0 for this to work. See
 [the release notes](https://maven.apache.org/docs/3.5.0/release-notes.html) for more information.
 You also need to run your Maven build with at least Java 8 (due to the [JGit](https://eclipse.org/jgit) dependency).
 
-For *earlier* Maven versions, you need to manually download [the JAR file](https://repo.maven.apache.org/maven2/com/github/pascalgn/properties-maven-extension/)
-and place it in the `${MAVEN_HOME}/lib/ext` folder.
-
 ## Properties
 
 The following properties are currently provided by the extension:

pom.xml

@@ -69,6 +69,30 @@
 
     <build>
         <plugins>
+            <plugin>
+                <artifactId>maven-enforcer-plugin</artifactId>
+                <version>3.0.0-M3</version>
+                <executions>
+                    <execution>
+                        <id>enforce-maven</id>
+                        <goals>
+                            <goal>enforce</goal>
+                        </goals>
+                        <configuration>
+                            <rules>
+                                <requireJavaVersion>
+                                    <version>[1.8.0,)</version>
+                                    <message>Wrong Java version. It should be 1.8.0 or higher!</message>
+                                </requireJavaVersion>
+                                <requireMavenVersion>
+                                    <version>[3.5.0,)</version>
+                                    <message>Wrong Maven version. It should be 3.5.0 or higher!</message>
+                                </requireMavenVersion>
+                            </rules>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
@@ -192,13 +216,13 @@
         <dependency>
             <groupId>org.eclipse.jgit</groupId>
             <artifactId>org.eclipse.jgit</artifactId>
-            <version>5.7.0.202003110725-r</version>
+            <version>5.9.0.202009080501-r</version>
         </dependency>
 
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <version>4.13</version>
+            <version>4.13.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>