Should really pin the python dependencies for improving reproducible builds

[Adam Dyess]

The requirements.txt on this charm specifically in release branches allows floating of many of the python dependencies. This floating has been known to cause issues like the following https://github.com/canonical/operator/issues/1225 when we're in the middle of trying to release a charm. This can derail a release for multiple days and can cause waits/delays of the release for weeks until patches are made.

Using dependabot on the repos to trigger updates to the requirements.txt is an improvement to just having floating deps.

[Adam Dyess (addyess)]

https://github.com/charmed-kubernetes/charm-kubeapi-load-balancer/pull/38
https://github.com/charmed-kubernetes/charm-kubernetes-worker/pull/173
https://github.com/charmed-kubernetes/charm-kubernetes-control-plane/pull/344

[Adam Dyess (addyess)]

Once merged, we'll need to backport with cherry-picks to release_1.30 and release_1.29 branches

[Adam Dyess (addyess)]

KLB backports:
https://github.com/charmed-kubernetes/charm-kubeapi-load-balancer/commit/03ab179f837d9dd7cc44e70893c5afa78e2db077
https://github.com/charmed-kubernetes/charm-kubeapi-load-balancer/commit/b5637fa939b11d6943240ba95612b03338d5217e

KCP:
https://github.com/charmed-kubernetes/charm-kubernetes-control-plane/commit/e2b8b5c66e0274855391b277f7c812e808f10b14
https://github.com/charmed-kubernetes/charm-kubernetes-control-plane/commit/84edf25e3c72c31e3255df2d0f391b8f2b7734c2

KW:
https://github.com/charmed-kubernetes/charm-kubernetes-worker/commit/344c884152a4286144e3e5a7ddfaeca42ce867f0
https://github.com/charmed-kubernetes/charm-kubernetes-worker/commit/f9a6a36a7f8a9d2875a9999c55cc87139e74c7dc