Update maven-compiler-plugin to v. 3.4.0

P/Sd1/Array/arraycalcExercise/pom.xml

@@ -42,7 +42,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>3.0.1</version>
+        <version>3.4.0</version>
         <configuration>
 	  <linksource>true</linksource>
 	  <additionalOptions>

P/Sd1/Array/integerStoreSkeleton/pom.xml

@@ -45,7 +45,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>3.0.1</version>
+        <version>3.4.0</version>
         <configuration>
 	  <linksource>true</linksource>
 	  <additionalOptions>

P/Sda1/Jdbc/Insert/Prepared/pom.xml

@@ -74,7 +74,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-shade-plugin</artifactId>
-        <version>3.1.0</version>
+        <version>3.4.0</version>
         <configuration>
           <transformers>
             <transformer