chore: only tag/push latest Docker for latest semantic tag

[markphelps]

This should fix the issue where creating a backport release was incorrectly also tagging the image as latest and pushing to our Docker registries

This removes the tagging of latest from goreleaser workflow and instead tags and pushes the image only if it is actually the most recent semantic release.

I tested this locally by writing a little script:

# test.sh

if [[ $(git tag -l --sort=-version:refname | head -n 1) == $TAG ]]; then
    echo "MATCH"
else
    echo "NO MATCH"
fi

$ ./test.sh
NO MATCH

$ TAG=v1.15.1 ./test.sh
NO MATCH

$ TAG=v1.15.2 ./test.sh
MATCH

[markphelps]

gah, this does break the nightly tag tho..

[markphelps]

I think I fixed it by breaking out nightly into its own .goreleaser.nightly.yml and using the includes functionality of goreleaser

[GeorgeMac]

I've been seeing this block on cockroach a lot lately. This is an attempt to see if waiting for SQL helps: #1183

[GeorgeMac]

Nice.