chore!: update minimum go version

[toddbaert]

Add replace directive for broken package.

https://go.buf.build/open-feature/flagd-connect/open-feature/flagd no longer resolves (this has been deprecated).

Unfortunately, for some reasons, this is still being added to some go.sum files. I have no idea why, I can't seem to force it to be updated. This adds a replace directive for this dep.

To fix this, we have to drop support for 1.16 and lower, it seems: #291 (comment)

Github did something really odd and stopped updating this PR even though I was pushing new commits. See here.

[toddbaert]

@Kavindu-Dodan this is the "bad" dep. Its seems to be coming in via the sdk, but I can't understand why (the SDK version seems new enough that it shouldn't need this).

[toddbaert]

@Kavindu-Dodan I figured it out. It seem the issue is related to the go 1.13 compatibility in the config-cat module. Moving this to 1.18, and doing go mod tidy -compat=1.18 fixes the issue.

cc @rcrowe are you OK to migrate this to 1.18? That's also the version required by the latest SDK.

[toddbaert]

cc @thomaspoignant very interesting stuff here - looks like this should resolve our CI issues.

[Kavindu-Dodan]

@Kavindu-Dodan I figured it out. It seem the issue is related to the go 1.13 compatibility in the config-cat module. Moving this to 1.18, and doing go mod tidy -compat=1.18 fixes the issue.

cc @rcrowe are you OK to migrate this to 1.18? That's also the version required by the latest SDK.

Another alternative is to release go-sdk version which removes the circular dependency at go-sdk [1] & update this

[1] - open-feature/go-sdk#205