Add formatting to tables in documentation

[Ivan Dneprov]

Add formatting to tables in documentation.
Now it looks like this:

|`spring-data-tarantool` Version | Spring Boot Version
| :----------- | :----: |
|0.x.x | 2.2.x

I recommend to make it like this:

| `spring-data-tarantool` Version | Spring Boot Version |
|:--------------------------------|:-------------------:|
| 0.x.x                           |        2.2.x        |