Use the go sql context functions (ExecContext, QueryContext etc...)
The context is saved inside Tx so the library users should only pass it one time
to the db.Do function.
Since we are using the shared cache with the lock notify we won't receive
SQLITE_BUSY errors but we could receive SQLITE_LOCKED errors due to deadlocks or
locked tables on concurrent read and write transactions.
This patch catches this kind of errors and retries the tx until maxTxRetries.
Just a raw replace of "github.com/pkg/errors".
Next steps will improve errors (like remote errors, api errors, not exist errors
etc...) to leverage its functionalities
Simone Gotti