update all dependencies (maven artifacts)

- PDF dependency was missing in the pom file the JDK8
  * We should think about creating a parent pom - in that case all plantuml dependencies could be in the parent pom and we would only the mantain one pom file.
    (It is also possible to drop the Java 8 support.)
  * Why do we not have any PDF tests?
- add rule to ignore version update hint with `-dev` followed by a dot and date (e.g. `0.37.0-dev.20230308`)
- migration from JUnit4 to JUnit5

src/test/java/net/sourceforge/plantuml/servlet/TestCheck.java

@@ -4,6 +4,9 @@ import java.io.IOException;
 import java.net.URL;
 import java.net.URLConnection;
 
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
 import net.sourceforge.plantuml.servlet.utils.TestUtils;
 import net.sourceforge.plantuml.servlet.utils.WebappTestCase;
 
@@ -14,36 +17,38 @@ public class TestCheck extends WebappTestCase {
      * Verifies the generation of a syntax check for the following sample:
      * Bob -> Alice : hello
      */
+    @Test
     public void testCorrectSequenceDiagram() throws IOException {
         final URL url = new URL(getServerUrl() + "/check/" + TestUtils.SEQBOB);
         final URLConnection conn = url.openConnection();
         // Analyze response
         // Verifies the Content-Type header
-        assertEquals(
-            "Response content type is not TEXT PLAIN or UTF-8",
+        Assertions.assertEquals(
             "text/plain;charset=utf-8",
-            conn.getContentType().toLowerCase()
+            conn.getContentType().toLowerCase(),
+            "Response content type is not TEXT PLAIN or UTF-8"
         );
         // Get the content, check its first characters and verify its size
         String checkResult = getContentText(conn);
-        assertTrue(
-            "Response content is not starting with (2 participants)",
-            checkResult.startsWith("(2 participants)")
+        Assertions.assertTrue(
+            checkResult.startsWith("(2 participants)"),
+            "Response content is not starting with (2 participants)"
         );
         int checkLen = checkResult.length();
-        assertTrue(checkLen > 1);
-        assertTrue(checkLen < 100);
+        Assertions.assertTrue(checkLen > 1);
+        Assertions.assertTrue(checkLen < 100);
     }
 
     /**
      * Check the syntax of an invalid sequence diagram :
      * Bob -
      */
+    @Test
     public void testWrongDiagramSyntax() throws IOException {
         final URL url = new URL(getServerUrl() + "/check/SyfFKj050000");
         // Analyze response
         String checkResult = getContentText(url);
-        assertTrue("Response is not an error", checkResult.startsWith("(Error)"));
+        Assertions.assertTrue(checkResult.startsWith("(Error)"), "Response is not an error");
     }
 
 }