Add signature cert and package identifier parameters to package script

[cmcgee1024]

When building macOS packages with pkgbuild, a signing certificate needs to be provided up-front, as is the package identifier. Change the package script so that it can accept the location of the certificate and override the package identifier.

[cmcgee1024]

@swift-ci test macOS

[cmcgee1024]

@swift-ci test macOS

[cmcgee1024]

macOS tests are all passing:

Test Suite 'All tests' passed at 2024-10-21 10:56:53.919.
	 Executed 66 tests, with 0 failures (0 unexpected) in 86.823 (86.831) seconds

[shahmishal]

@cmcgee1024 Do you know what's going on here for macOS failure?

swiftpm_testing_helper/Entrypoint.swift:29: Fatal error: Failed to open test bundle at path /Users/ec2-user/jenkins/workspace/pr-swiftly-macos/branch-main/swiftly/.build/arm64-apple-macosx/debug/swiftlyPackageTests.xctest/Contents/MacOS/swiftlyPackageTests: dlopen(/Users/ec2-user/jenkins/workspace/pr-swiftly-macos/branch-main/swiftly/.build/arm64-apple-macosx/debug/swiftlyPackageTests.xctest/Contents/MacOS/swiftlyPackageTests, 0x0101): Library not loaded: @rpath/XCTest.framework/Versions/A/XCTest

[cmcgee1024]

swiftpm_testing_helper/Entrypoint.swift:29: Fatal error: Failed to open test bundle at path /Users/ec2-user/jenkins/workspace/pr-swiftly-macos/branch-main/swiftly/.build/arm64-apple-macosx/debug/swiftlyPackageTests.xctest/Contents/MacOS/swiftlyPackageTests: dlopen(/Users/ec2-user/jenkins/workspace/pr-swiftly-macos/branch-main/swiftly/.build/arm64-apple-macosx/debug/swiftlyPackageTests.xctest/Contents/MacOS/swiftlyPackageTests, 0x0101): Library not loaded: @rpath/XCTest.framework/Versions/A/XCTest

@shahmishal I don't have any insights into this error, but there is some analysis here: #172 (comment)