Fix dependency declaration of Prometheus

[ctron]

This is battle between Golang authors and Prometheus authors (probably some others as well).

Golang requires semantic versioning, and Prometheus doesn't want submit to those rules:

• With Go 1.13 can no longer flag versions as incompatible, if the have a 'go.mod' file in their repository: invalid version: module contains a go.mod file, so major version must be compatible: should be v0 or v1, not v2  golang/go#35732
• Dropping the '+incompatible' suffix is not possible, because the module author (Prometheus) would need to add the suffix '/v2' to their module. Otherwise you run into: invalid version: module contains a go.mod file, so major version must be compatible: should be v0 or v1, not v2  golang/go#35732 (comment)
• Prometheus doesn't care about Golang's idea of versioning and simply ignores it: Go get failing with go1.13 prometheus/prometheus#6048 (comment)

You can still put a commit has into the go.mod file as version, but that gets translated to into a version from the past (for 2.15.2 prometheus this will resolve into 2.3.x or 1.8.x).

The solution to all of this insanity is, to declare the version you had in mind in the "requires" section. And then add a mapping entry into the "replace" section, pointing to the actual version, using a commit hash and the "v0.0.0" version.

Type of change

• Rant
• Bugfix

Description

Checklist

• Update/write design documentation in ./documentation/design
• Write tests and make sure they pass
• Update documentation
• Check RBAC rights for Kubernetes / OpenShift roles
• Try your changes from Pod inside your Kubernetes and OpenShift cluster, not just locally
• Reference relevant issue(s) and close them after merging
• Update CHANGELOG.md

[lulf]

LGTM, but lets keep it serious in the commit messages (although I 100% agree with it :) )