GRDB.swift breaking changes

Improve the ergonomics of [`DatabaseMigrator.registerMigration(_:foreignKeyChecks:merging:migrate)`](https://swiftpackageindex.com/groue/grdb.swift/documentation/grdb/databasemigrator/registermigration(_:foreignkeychecks:merging:migrate:)) by accepting that the name of the merged migration is included in the set of merged migrations: ```swift // Used to fail, now OK: migrator.registerMigration("v3", merging: ["v1", "v2", "v3"]) { ... } // ~~~~ ~~~~ // The above code is equivalent to: migrator.re

enum Columns { ... }

`TableAlias` is now a generic type. This will break existing code that accepts a `TableAlias` as an argument. You will have to make those methods generic as well.

public enum Columns { ... } } ```

If you define a `public` record type with a nested `Columns` enum, you have to make this enum `public` as well. ```diff public struct Player: FetchableRecord, PersistableRecord {

**Breaking Change**: Coding strategies depend on the column by [@groue](https://github.com/groue) in [#1606](https://github.com/groue/GRDB.swift/pull/1606)

**Breaking Change**: Enhance ergonomics of record methods that insert/save/upsert and fetch by [@groue](https://github.com/groue) in [#1599](https://github.com/groue/GRDB.swift/pull/1599)

**Breaking Change**: Rename the CSQLite module to GRDBSQLite, and stop exporting the C SQLite functions by [@groue](https://github.com/groue) in [#1600](https://github.com/groue/GRDB.swift/pull/1600)

**Breaking Change**: Perform all writes with immediate transactions by default by [@groue](https://github.com/groue) in [#1602](https://github.com/groue/GRDB.swift/pull/1602)

**Breaking Change**: Remove DatabasePool.concurrentRead by [@groue](https://github.com/groue) in [#1603](https://github.com/groue/GRDB.swift/pull/1603)

**Breaking Change**: enhance ergonomics of record methods that insert/save/upsert and fetch by @groue in https://github.com/groue/GRDB.swift/pull/1599

**Breaking Change**: Rename the CSQLite module to GRDBSQLite, and stop exporting the C SQLite functions. by @groue in https://github.com/groue/GRDB.swift/pull/1600

**Breaking Change**: Perform all writes with immediate transactions by default by @groue in https://github.com/groue/GRDB.swift/pull/1602

**Breaking Change**: Remove DatabasePool.concurrentRead by @groue in https://github.com/groue/GRDB.swift/pull/1603

**Breaking Change**: Coding strategies depend on the column by @groue in https://github.com/groue/GRDB.swift/pull/1606