Merge pull request #220 from package-url/scratch/refactor-stringutils

chore!: refactor PackageURL by moving String functions to StringUtil

Author: stevespringett

src/main/java/com/github/packageurl/MalformedPackageURLException.java

@@ -53,7 +53,7 @@ public MalformedPackageURLException(@Nullable String msg) {
      *
      * @param message the detail message
      * @param cause the cause
-     * @since 1.6.0
+     * @since 2.0.0
      */
     public MalformedPackageURLException(String message, Throwable cause) {
         super(message, cause);
@@ -64,7 +64,7 @@ public MalformedPackageURLException(String message, Throwable cause) {
      * message of {@code (cause==null ? null : cause.toString())}.
      *
      * @param cause the cause
-     * @since 1.6.0
+     * @since 2.0.0
      */
     public MalformedPackageURLException(Throwable cause) {
         super(cause);