chore: replace interface{} with any

[romshark]

This is the result of running:

find . -name "*.go" ! -exec grep -q "// Code generated" {} \; -exec gofmt -w -r 'interface{} -> any' {} +

It safely replaces all usage of interface{} with any, excluding generated files and is hence a purely cosmetic change.

Also see golang/go#49884

[jiceatscion]

This change is 

[jiceatscion]

Good idea. I support this.

Reviewed 72 of 73 files at r1, 3 of 3 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @oncilla and @romshark)

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a discussion (no related file):
I shouldn't be the sole approver of a scion assoc PR. So I add this to prevent approval until there's another one.

[jiceatscion]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @oncilla and @romshark)