ADD: PRAGMA cipher_compatibility

[safiir]

The cipher_compatibility pragma should be called immediately after if provided in dsn for indicating backward compatibility
requirement (eg. from v4 -> v3), but not considered previously, so it lead to error file is not a database, because synchronous pragma is always executed even if cipher_compatibility pragma is not executed.

[ValentinMontmirail]

I took your Pull Request @safiir inside my fork() of this repository.
See ValentinMontmirail#10

I try to maintain the fork() to the latest version of SQLite3 and SQLCipher.
I am currently supporting SQLite 3.45.0.
Feel free to do PR directly there if you want to improve this lib.