v3.26.0

Added

• Compile an experimental native executable for Apple Silicon #1339 (yob)
  • Using a pre-release version of go, we'll switch to compiling with go 1.16 once it's released

Changed

• Install script: use the arm64 binary for aarch64 machines #1340 (gc-plp)
• Build with golang 1.15 #1334 (yob)
• Bump alpine docker image from alpine 3.8 to 3.12 #1333 (yob)
• Upgrade docker ubuntu to 20.04 focal #1312 (sj26)