downgrade go-difflib and go-spew to tagged releases

[thaJeztah]

relates to:

• downgrade go-difflib and go-spew to tagged releases #2921
• chore: remove unneeded excludes #3552

This reverts commit 17952c6. This re-applies commit 1ef9e67

Some of the new dependencies reintroduced these;

    go mod graph | grep ' github.com/davecgh/[email protected]'
    github.com/docker/buildx github.com/davecgh/[email protected]
    github.com/google/[email protected] github.com/davecgh/[email protected]
    github.com/moby/[email protected] github.com/davecgh/[email protected]
    github.com/open-policy-agent/[email protected] github.com/davecgh/[email protected]
    github.com/sigstore/[email protected] github.com/davecgh/[email protected]
    github.com/sigstore/rekor-tiles/[email protected] github.com/davecgh/[email protected]
    github.com/sigstore/[email protected] github.com/davecgh/[email protected]

[jsternberg]

@thaJeztah how important is this? The replace areas inside of go.mod prevent installing the module with the go tool and it doesn't seem to me like using the released versions of those two dependencies is all that important. Are they used for anything beyond testing?