Build tools sometimes fail to download

[petewall]

On systems where the development and build tools aren't installed, we try to run them via docker images:

ifdef HAS_HELM_DOCS
	helm-docs --chart-to-generate .
else
	docker run --rm --volume "$(shell pwd):/helm-docs" -u $(shell id -u) jnorwood/helm-docs:latest
endif

Sometimes these fail:

docker run --rm --volume "/home/runner/work/k8s-monitoring-helm/k8s-monitoring-helm/charts/k8s-monitoring/charts/feature-annotation-autodiscovery:/helm-docs" -u 1001 jnorwood/helm-docs:latest
Unable to find image 'jnorwood/helm-docs:latest' locally
latest: Pulling from jnorwood/helm-docs
ec99f8b99825: Pulling fs layer
c77a463dfa03: Pulling fs layer
2115c7c95dc5: Pulling fs layer
docker: error pulling image configuration: download failed after attempts=1: error parsing HTTP 403 response body: no error details found in HTTP response body: "{\"status\":403,\"message\":\"Error: invalid URL signature\"}".

It might be nice to build a single image "grafana/k8s-monitoring-helm-chart-build-tools" that contains all of the tools, so a docker image need be pulled just once.

[petewall]

Also helm-schema gen:

karuppiah7890/helm-schema-gen info checking GitHub for tag '0.0.4'
karuppiah7890/helm-schema-gen info found version: 0.0.4 for 0.0.4/Linux/x86_64
karuppiah7890/helm-schema-gen info installed ./bin/helm-schema-gen
Illegal instruction
Error: plugin install hook for "schema-gen" exited with error