Automate Flux version bump

[makkes]

trafficstars

Locations where Flux version is referenced:

• [x] Flux CLI version in the Makefile (done via https://github.com/weaveworks/weave-gitops/blob/main/.github/workflows/upgrade-flux.yaml#L43-L44)
• [x] Go Modules (done via https://github.com/weaveworks/weave-gitops/blob/main/.github/workflows/upgrade-flux.yaml#L43-L44)
• [ ] s-c to Flux version map in the Go source code

Acceptance Criteria

• The automation should be implemented as a GitHub Action
• Whenever a new Flux version is released, a PR is automatically created in the weave-gitops repository that bumps the version in all the places stated above.

[lasomethingsomething]

Set priority to low in light of Flux 2.0 release and an assumption that the impact we felt in January is lower now. Feel free to challenge that if we're missing facts.

[makkes]

an assumption that the impact we felt in January is lower now

Not sure what that impact was but I think the Flux version bump process hasn't changed since.

[lasomethingsomething]

@makkes Per Yiannis we've done the first two items (see https://github.com/weaveworks/weave-gitops/blob/main/.github/workflows/upgrade-flux.yaml#L43-L44). For the third, what still needs to change?

[makkes]

The third item

s-c to Flux version map in the Go source code

is about this map. This can be automated by a pretty simple script looking up the s-c version for a given Flux version.