RC2 compile using net6

RC1

version 1.5

Version

Merge remote-tracking branch 'origin/master' into v1.3

Merge branch 'gus/notes-for-131' into v1.3

Merge branch 'gus/notes-for-131' into v1.3

Merge pull request fsprojects#513 from fsprojects/v1.3-fsharp-core-6

V1.3 F# core 6

Merge pull request fsprojects#513 from fsprojects/v1.3-fsharp-core-6

V1.3 F# core 6