Update GRDB.swift for Swift 5.3

[groue]

Pull Request Description

Hello, this pull request adds compatibility check for GRDB 5.9.0 and Swift 5.3.

Acceptance Criteria

To be accepted into the Swift source compatibility test suite, a project must:

• be an Xcode or swift package manager project
• support building on either Linux or macOS
• target Linux, macOS, or iOS/tvOS/watchOS device
• be contained in a publicly accessible git repository
• maintain a project branch that builds against Swift 4.0 and passes any unit tests
• have maintainers who will commit to resolve issues in a timely manner
• be compatible with the latest GM/Beta versions of Xcode and swiftpm
• add value not already included in the suite
• be licensed with one of the following permissive licenses:
  • BSD
  • MIT
  • Apache License, version 2.0
  • Eclipse Public License
  • Mozilla Public License (MPL) 1.1
  • MPL 2.0
  • CDDL
• pass ./project_precommit_check script run

$ ./project_precommit_check GRDB.swift --earliest-compatible-swift-version 5.3
** CHECK **
--- Validating GRDB.swift Swift version 5.3 compatibility ---
--- Project configured to be compatible with Swift 5.3 ---
--- Checking GRDB.swift platform compatibility with Darwin ---
--- Platform compatibility check succeeded ---
--- Locating swiftc executable ---
$ xcrun -f swiftc
--- Checking installed Swift version ---
$ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc --version
--- Version check failed ---
Expected version:
Apple Swift version 5.3.2 (swiftlang-1200.0.45 clang-1200.0.32.28)
Target: x86_64-apple-darwin20.3.0

Current version:
Apple Swift version 5.4.2 (swiftlang-1205.0.28.2 clang-1205.0.19.57)
Target: x86_64-apple-darwin20.6.0

warning: Unexpected swiftc version. Expected swiftc for Swift 5.3 can be found in Xcode 12.4 (contains Swift 5.3.2).
warning: Continuing to build with unexpected swiftc version.

--- Executing build actions ---
$ /Users/groue/Documents/git/groue/swift-source-compat-suite/runner.py --swift-branch swift-5.3-branch --swiftc /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc --projects /Users/groue/Documents/git/groue/swift-source-compat-suite/projects.json --include-repos 'path == "GRDB.swift"' --include-versions 'version == "5.3"' --include-actions 'action.startswith("Build")'
PASS: GRDB.swift, 5.3, d29010, Swift Package
========================================
Action Summary:
     Passed: 1
     Failed: 0
    XFailed: 0
    UPassed: 0
      Total: 1
========================================
Repository Summary:
      Total: 1
========================================
Result: PASS
========================================
--- GRDB.swift checked successfully against Swift 5.3 ---

[shahmishal]

@swift-ci test

[groue]

Hello, is there something I can do in order to help merging this pull request?

[shahmishal]

  | PASS_GRDB.swift_4.2_BuildSwiftPackage.log 
  | PASS_GRDB.swift_5.0_BuildSwiftPackage.log
  | PASS_GRDB.swift_5.1_BuildSwiftPackage.log
  | PASS_GRDB.swift_5.3_BuildSwiftPackage.log