chore bump to 0.2.0

[github-actions[bot]]

Read:

+--------------------------------------------+---------+---------+
|                                            | tonbo   | rocksdb |
+================================================================+
| random range reads                         | 89747ms | 37519ms |
|--------------------------------------------+---------+---------|
| random range reads                         | 81563ms | 37289ms |
|--------------------------------------------+---------+---------|
| random range projection reads              | 39760ms | 36425ms |
|--------------------------------------------+---------+---------|
| random range projection reads              | 41426ms | 36909ms |
|--------------------------------------------+---------+---------|
| random range projection reads (4 threads)  | 33055ms | 37026ms |
|--------------------------------------------+---------+---------|
| random range projection reads (8 threads)  | 31654ms | 37156ms |
|--------------------------------------------+---------+---------|
| random range projection reads (16 threads) | 28513ms | 35937ms |
|--------------------------------------------+---------+---------|
| random range projection reads (32 threads) | 23733ms | 35555ms |
+--------------------------------------------+---------+---------+

[github-actions[bot]]

Write:

+-------------------------------+--------+---------+
|                               | tonbo  | rocksdb |
+==================================================+
| bulk load                     | 6378ms | 9383ms  |
|-------------------------------+--------+---------|
| individual writes             | 8320ms | 10727ms |
|-------------------------------+--------+---------|
| individual writes (4 threads) | 8181ms | 10990ms |
|-------------------------------+--------+---------|
| individual writes (8 threads) | 7711ms | 10803ms |
|-------------------------------+--------+---------|
| batch writes                  | 8019ms | 7132ms  |
|-------------------------------+--------+---------|
| batch writes (4 threads)      | 8022ms | 7111ms  |
|-------------------------------+--------+---------|
| batch writes (8 threads)      | 7623ms | 7069ms  |
|-------------------------------+--------+---------|
| removals                      | 3088ms | 3823ms  |
+-------------------------------+--------+---------+