Java libs need manifest.MF versions

[melloware]

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.2.2</version>
            <configuration>
                <archive>
                    <manifest>
                            <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                            <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
                        </manifest>
                </archive>
            </configuration>
        </plugin>

This way I can do io.nayuki.qrcodegen.QrCode.class.getPackage().getImplementationVersion() and return "1.8.0"