Update maven plugins

- maven-enforcer-plugin 3.0.0
- maven-javadoc-plugin 3.3.1
- maven-pmd-plugin 3.15.0
- org.eclipse.cbi.maven.plugins:eclipse-jarsigner-plugin 1.3.2
- org.springframework.boot:spring-boot-maven-plugin 2.5.4

Change-Id: I377732b651f3718060c58ca48993e0c3ac79fa8b

org.eclipse.jgit.packaging/pom.xml

@@ -165,7 +165,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-enforcer-plugin</artifactId>
-        <version>3.0.0-M3</version>
+        <version>3.0.0</version>
         <executions>
           <execution>
             <id>enforce-maven</id>
@@ -294,7 +294,7 @@
         <plugin>
           <groupId>org.eclipse.cbi.maven.plugins</groupId>
           <artifactId>eclipse-jarsigner-plugin</artifactId>
-          <version>1.3.1</version>
+          <version>1.3.2</version>
         </plugin>
         <plugin>
           <groupId>org.codehaus.mojo</groupId>

pom.xml

@@ -168,7 +168,7 @@
     <httpcore-version>4.4.14</httpcore-version>
     <slf4j-version>1.7.30</slf4j-version>
     <log4j-version>1.2.15</log4j-version>
-    <maven-javadoc-plugin-version>3.2.0</maven-javadoc-plugin-version>
+    <maven-javadoc-plugin-version>3.3.1</maven-javadoc-plugin-version>
     <tycho-extras-version>1.7.0</tycho-extras-version>
     <gson-version>2.8.7</gson-version>
     <bouncycastle-version>1.69</bouncycastle-version>
@@ -301,7 +301,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-pmd-plugin</artifactId>
-          <version>3.14.0</version>
+          <version>3.15.0</version>
           <configuration>
             <sourceEncoding>utf-8</sourceEncoding>
             <minimumTokens>100</minimumTokens>
@@ -324,7 +324,7 @@
         <plugin>
           <groupId>org.eclipse.cbi.maven.plugins</groupId>
           <artifactId>eclipse-jarsigner-plugin</artifactId>
-          <version>1.1.7</version>
+          <version>1.3.2</version>
         </plugin>
         <plugin>
           <groupId>org.eclipse.tycho.extras</groupId>
@@ -391,7 +391,7 @@
         <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
-          <version>2.4.4</version>
+          <version>2.5.4</version>
         </plugin>
       </plugins>
     </pluginManagement>
@@ -400,7 +400,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-enforcer-plugin</artifactId>
-        <version>3.0.0-M3</version>
+        <version>3.0.0</version>
         <executions>
           <execution>
             <id>enforce-maven</id>