Updated Java security project reference.

[savankansagra]

Previous URL is not working. So find out new Resource https://spring.io/guides/gs/securing-web/ and I have tested the resource. It looks good.

Description

Previous URL is not working. So find out new Resource https://spring.io/guides/gs/securing-web/ and I have tested the resource. It looks good.

Motivation and Context

Click on resource was not working. because Original Content creator has removed the resource.
broken link in java tutorial #347

How Has This Been Tested?

I have implemented and tested entire code in my local.
Manual Testing. Used Spring tool suite as IDE and created springboot project in that.

Not any effect to other code.

Types of changes

• Content Update (change which fixes an issue or updates an already existing submission)
• New Article (change which adds functionality)
• Documentation change

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• [ x] I have made checks to ensure URLs and other resources are valid

[enkeyz]

Thanks!