Support repeatable migration.

[YixingCheng]

Hi Nikita,
Thanks for making this handy tool.
One feature I would like to have in this tool is the support for Repeatable migration in flyway.
Currently when I have a R__xxx.sql, I am getting

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'r2dbcMigrate' defined in class path resource [name/nkonev/r2dbc/migrate/autoconfigure/R2dbcMigrateAutoConfiguration.class]: Invocation of init method failed; nested exception is java.lang.NumberFormatException: For input string: "R"

I am using the latest release.

[nkonev]

Hello @YixingCheng
repeatable migrations (in Flyway definition) requires checksums. This tool currently doesn't support checksums.

PRs are welcome