v1.21.0

What's Changed

• Bump back to alpha post 1.20.0 release by @Mpdreamz in #2025
• Fix NRE in exception logging by @z1c0 in #2026
• Clarify 64 bit only support in the profiler docs. by @gregkalapos in #2037
• Remove ETW powered GC metrics on FullFramework by @Mpdreamz in #2036
• Migrate specs update to updatecli by @reakaleek in #2034
• Remove unsupported TFM's by @Mpdreamz in #2027
• Prevent sending activation_method in metadata for 8.7.0 by @Mpdreamz in #2041
• Prepare 1.21.0 release by @Mpdreamz in #2042

Full Changelog: v1.20.0...v1.21.0