Fix linting errors and use of deprecated repositories

[steven-sheehy]

What this PR does / why we need it:

• Switch away from deprecated chart repositories
• Bump dependencies to fix linting errors when mixing loki with kube-prometheus-stack

Error:  templates/: template: charts/loki-stack/charts/grafana/templates/deployment.yaml:48:10: executing "loki-stack/charts/grafana/templates/deployment.yaml" at <include "grafana.pod" .>: error calling include: template: kube-prometheus-stack/charts/grafana/templates/_pod.tpl:18:102: executing "grafana.pod" at <.Values.sidecar.notifiers.enabled>: nil pointer evaluating interface {}.enabled

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Documentation added
• Tests updated

[steven-sheehy]

Side note: Are there plans to move Loki chart to https://github.com/grafana/helm-charts as well or will it stay in this repo?

[codecov-io]

Codecov Report

Merging #2742 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2742      +/-   ##
==========================================
- Coverage   61.39%   61.36%   -0.03%     
==========================================
  Files         173      173              
  Lines       13465    13465              
==========================================
- Hits         8267     8263       -4     
- Misses       4445     4448       +3     
- Partials      753      754       +1     

Impacted Files	Coverage Δ
pkg/promtail/targets/file/tailer.go	70.09% <0.00%> (-5.61%)	⬇️
pkg/logql/evaluator.go	92.81% <0.00%> (+0.42%)	⬆️

[cyriltovena]

LGTM Thanks @steven-sheehy