With go 1.17 a change to the build flags was implemented:
https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md
The formatter now automatically adds the forward-compatible build tag
format and the linter checks for them, so we need to include them in our
code.
This commit again enables anchor channels by default.
During itests we still keep anchors opt-in, as many of the tests rely on
the behaviour of non-anchor channels.
This commit reverts the anchors-by-default change, and instead make
anchor commitments and opt-in option. The plan is to enable anchors by
default further down the line.
