[20.10] Update Go to 1.16.9
go1.16.9 (released 2021-10-07) includes a security fix to the linker and misc/wasm
directory, as well as bug fixes to the runtime and to the text/template package.
See the Go 1.16.9 milestone on our issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.16.9+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>