Fix generate-allocs command name in readme
It's generate-allocs, not generate-alloc
It's generate-allocs, not generate-alloc
```
- generate genesis allocs (using private keys and/or addresses)
```
`./bin/mantis cli generate-alloc --balance=42 --address=8b196738d90cf3d9fc299e0ec28e15ebdcbb0bdcb281d9d5084182c9c66d5d12 --key=00b11c32957057651d56cd83085ef3b259319057e0e887bd0fdaee657e6f75d1`
`./bin/mantis cli generate-allocs --balance=42 --address=8b196738d90cf3d9fc299e0ec28e15ebdcbb0bdcb281d9d5084182c9c66d5d12 --key=00b11c32957057651d56cd83085ef3b259319057e0e887bd0fdaee657e6f75d1`
```
- generate multiple key-pairs (following example generate 5 key-pairs)
```
Change testcoin description