Bump dependencies to the head of their respective branches

[spouliot]

Commit list for xamarin/Xamarin.MacDev:

• xamarin/Xamarin.MacDev@39ea45b Add README to point people to xamarin-macios and matching LICENSE (Totally remove the old nunitlite #27)
• xamarin/Xamarin.MacDev@aa495d0 Add ClassKit entitlements key ([CoreMedia] Add convenience byte [] overloads to CMBlockBuffer API #26)
• xamarin/Xamarin.MacDev@29e500b Added a public SdkDir property to MonoMacSdk (Switch to using nunitlite submodule from the mono repo. #25)
• xamarin/Xamarin.MacDev@1a3eeb0 Add NFC entitlement key to EntitlementKeys ([Contacts] Fix wrong delegate signature on CNContactStoreEnumerateContactsHandler #22)
• xamarin/Xamarin.MacDev@22a4d2e Add AllKeys property and GetEntitlementsKeys method ([msbuild/tests] Add TVServicesExtension test (wrong set of commits) #20)
• xamarin/Xamarin.MacDev@d3931ff Add missing data protection entitlement key (Correct delegate signature on CNContactStoreEnumerateContactsHandler #19)

Diff: xamarin/Xamarin.MacDev@2cff0d7...39ea45b

Commit list for xamarin/maccore:

• xamarin/maccore@76ab6a58ff Bump maciostools to the head of master in preparation for 15.8 branching
• xamarin/maccore@f22f7669d1 [AppleDocReader] Move to use a XamMac app so that we can use the compress lib. ([tests] Update project file. #820)
• xamarin/maccore@33a46996aa Ignore brew failures. ([xharness] Remove Classic logic from makefile generation. #823)
• xamarin/maccore@758aadc28a Use a custom keychain (xamarin-macios.keychain), and recreate it every time. ([avfoundation] Add missing setters on AVAssetDownloadOptions properties. Fixes #44201 #824)

Diff: https://github.com/xamarin/maccore/compare/b9702c7ec8fb6dd7dd7972b9bb145c6e82b9ac87...76ab6a58ff9061d35450f4bc75d075874a8489a8

[monojenkins]

Build failure
Build comment file:

✅ Provisioning succeeded
✅ Build succeeded
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✅ API Diff (from PR only)
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🔥 Test run failed 🔥

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[spouliot]

PR #4158 will fix the above error

[spouliot]

build

[monojenkins]

Build success
Build comment file:

✅ Provisioning succeeded
✅ Build succeeded
✅ API Diff (from stable)
✅ API Diff (from PR only)
✅ Generator Diff
✅ Test run succeeded

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