Migrate spring links for issues from jira to github

After Spring Framework's Migration from Jira to GitHub Issues old jira links doesn't work. 
See also: https://spring.io/blog/2019/01/15/spring-framework-s-migration-from-jira-to-github-issues

readme.md

@@ -114,7 +114,7 @@ Here is a list of them:
 
 | Name | Issue |
 |------|-------|
-| Spring JDBC: simplify usage of NamedParameterJdbcTemplate | [SPR-10256](https://jira.springsource.org/browse/SPR-10256) and [SPR-10257](https://jira.springsource.org/browse/SPR-10257) |
+| Spring JDBC: simplify usage of NamedParameterJdbcTemplate | [SPR-10256](https://github.com/spring-projects/spring-framework/issues/14889) and [SPR-10257](https://github.com/spring-projects/spring-framework/issues/14890) |
 | Bean Validation / Hibernate Validator: simplify Maven dependencies and backward compatibility |[HV-790](https://hibernate.atlassian.net/browse/HV-790) and [HV-792](https://hibernate.atlassian.net/browse/HV-792) |
 | Spring Data: provide more flexibility when working with JPQL queries | [DATAJPA-292](https://jira.springsource.org/browse/DATAJPA-292) |