Broken Image Links in README.adoc

[YangSiJun528]

It appears that the image URLs used in the README.adoc are incorrect.
The images are not displayed correctly on my device, showing as broken image files.

Screenshots:

The following image URLs seem to be invalid:

• https://spring.io/badges/spring-data-redis/ga.svg
• https://spring.io/badges/spring-data-redis/snapshot.svg