v5.0.0 Release

Note: This is a major release because it raised the min OS versions being supported. There are no breaking api changes to the core library.

What's Changed

• Generate current sources by @thomasvl in #684
• Generate current by @thomasvl in #685
• Generate updated services for current sources. by @thomasvl in #687
• Bump the min versions to match what Firebase will do for version 12. by @thomasvl in #688
• Remove some @available checks that are no long needed. by @thomasvl in #690
• Version bump to prepare for a release. by @thomasvl in #691

Full Changelog: v4.2.0...v5.0.0